The interpretation timeline
Matthew 18:20 Douay-Rheims

For where there are two or three gathered together in my name, there am I in the midst of them.

A.D. 407 – 1871 6 witnesses

Patristic

before A.D. 750
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“Yet He said not barely, Where they are gathered together, but added, in my name, as much as to say, If any man look upon Me as the chief motive of his love to his neighbour, I will be with him, though he is virtue be shewn towards other men. How is it then that those who thus agree together do not obtain what they ask for? First, because they ask things not expedient, and because they do not bring on their parts that which they ought to contribute; wherefore He says, If two of you, that is, who shew an evangelic conversation. Thirdly, because they pray seeking vengeance against those who have grieved them. And fourthly, because they seek mercy for sinners who have not repented.”
Source

Scholastic

c. 1100 – 1500
1256
A.D.
Thomas Aquinas Catholic
1225–1274
“"What do you think?" Here a comparison is set forth. And first the diligent search is set forth; second, the joy over the sheep found. Hence he says, "What do you think?" Thus it has been said that the Son of Man came to save what had perished, because the shepherd seeks the lost sheep. "If a man has a hundred sheep." By the number one hundred the whole universe of rational creatures is signified: ninety-nine is the same number as nine, but only multiplied, because nine multiplied by ten makes ninety; which number, namely nine, falls short of ten by a unit; hence by these sheep he signifies all rational creatures; John 10:27: "My sheep hear my voice"; Psalm 94:7: "but we are his people and the sheep of his pasture." By the sheep that strayed, the human race is signified. And why did he signify it by the sheep that strayed? Because through one man all strayed; 1 Peter 2:25: "you were like sheep going astray." "Does he not leave the ninety-nine in the mountains?" The text does not read "in the desert," but "in the mountains," as is found in the Greek. This is explained in three ways. First, because these ninety-nine signify the Angels who were left in the mountains, that is, in the heavenly places; Ezekiel 34:13: "I will feed them on the mountains of Israel." Or by the ninety-nine the just are signified, by the lost sheep sinners; and thus he left them in the mountains, that is, in the height of justice; Psalm 35:7: "your righteousness is like the mountains of God." Or by the ninety-nine the proud, by the sheep the humble: hence, "does he not leave the ninety-nine in the mountains," that is, in their pride, and go to seek the one that strayed? Psalm 118:176: "I have strayed like a sheep that is lost; seek your servant, O Lord." Next he deals with the joy: "and if it happens that he finds it," etc. Here too a threefold reason can be assigned. That the Lord rejoices over the good is found in Zephaniah 3:17: "your God will rejoice over you with gladness." If by the ninety-nine the Angels are signified, by the sheep man, the reason is plain, because man was worthy of being restored; Hebrews 2:16: "nowhere did he take hold of the Angels, but he took hold of the seed of Abraham." If by the ninety-nine we understand the just, likewise the reason is plain, because a commander loves more the soldier who falls in battle and afterward always fights manfully, than the one who never fell but always fights half-heartedly. Thus, when someone has sinned, and afterward rises up strongly and always conducts himself manfully, he loves him more; 2 Corinthians 7:9: "I rejoice, because you were made sorrowful unto repentance"; therefore the Lord rejoices more over him, etc., since he is of greater zeal. Yet this is not to be extended to all, because a just man can have so much zeal that he pleases God more than does the penitent. According to the third exposition also the reason is clear, because he rejoices more over the one who acknowledges his sin, as is clear in the case of the publican and the Pharisee. He concludes therefore thus: "It is not the will before your Father who is in heaven that one of these little ones should perish." He says less and signifies more, because his will is that they be saved; 1 Timothy 2:4: "who wills all men to be saved." For if he did not will it, he would not send the Angels. Ezekiel 18:23: "Is it my will that the wicked man should die? says the Lord." "If then your brother sins against you," etc. Here he deals with the forgiving of an offense. And first the order is set forth; second the number, at "then Peter, coming to him," etc. Concerning the first, three things. First he sets forth the secret admonition; second the testimony, at "but if he does not hear you," etc.; third the announcement, at "but if he does not hear them, tell it to the Church." Concerning the first, first he gives his teaching; second he assigns the reason for what was given, at "but if he hears you, you have gained your brother." Thus I have said that the little ones are not to be despised, but what is to be done if someone gives scandal? Here he teaches. "But if your brother sins against you, go and rebuke him between you and him alone." Note first that he says "has sinned": hence he speaks of a sin already perpetrated. Hence one must proceed differently with a sin already perpetrated than with one being perpetrated, because what has been perpetrated cannot become unperpetrated; hence while it is being perpetrated, one must take pains that it not happen; Isaiah 58:6: "undo the bonds of wickedness, loose the bundles that weigh down," etc. Hence while it is being perpetrated it is not necessary that such an order be kept; when it has been perpetrated, it is necessary. Again he says "against you." The Gloss: if he has inflicted an injury or an insult on you. Hence he means to say that we should forgive a sin done against us; but a sin that is done against God we cannot forgive, as the Gloss says. 1 Kings 2:25: "if a man sins against God, who shall pray for him?" Again, you ought especially to attend to injuries done by one who is with you in the same fellowship; of others too care must be had, but not so much. 1 Corinthians 5:12: "what have we to do with judging those who are outside?" "Go and rebuke him between you and him alone." The Lord leads the disciples to perfect solicitude and correction. Above, at 5:23, the Lord had said that if someone offended his brother, he should leave his gift before the altar, etc.; but here he goes further, because it is not only the one who injured, but the one who was injured: hence, "if he sins against you, go," etc.; Psalm 119:7: "with those who hated peace, I was peaceable." And should you forgive first? No; rather you ought first to rebuke: hence he does not command forgiving anyone, but the one who repents. Again he says "rebuke," not "upbraid" or "exasperate," and show it briefly. If he acknowledges it, then you ought to forgive; hence, "instruct them in a spirit of gentleness," Galatians 6:1. But does the one who omits this correction sin? Augustine: if you do not rebuke, you have become worse by keeping silent than he by sinning. But since it is true that all are bound to rebuke, someone might say that it belongs to prelates alone by office, but to others by charity. Sometimes the Lord permits the good to be punished along with the wicked. Why? Because they did not rebuke the wicked. Yet Augustine says that sometimes we ought to desist, if you fear that on account of this correction they will not be amended, but rendered worse. Again, if you fear it may bring on persecution of the Church, you do not sin. But if you desist so as not to be harmed in temporal things, so that no trouble befall you, or the like, you sin; Proverbs 9:8: "reprove a wise man, and he will love you." "Rebuke him between you and him alone." And why? Because this correction is done out of charity; and charity is the love of God and of neighbor. If you love, you ought to cherish his salvation. But in this two things must be attended to, namely conscience and good repute. If therefore you wish to save him, you ought to save his reputation; and this you will do by correcting him between you and him. If you rebuke him before everyone, you take away his reputation; yet conscience is to be preferred to reputation. Yet it frequently happens that when a man sees his sin made public, he becomes so shameless that he exposes himself to every sin; Jeremiah 2:20: "under every leafy tree you lay down, harlot"; Ecclesiasticus 4:25: "there is a shame that brings sin." But against this an objection is raised from 1 Timothy 5:20: "rebuke him that sins, before all." And this is true if the offense is public. For there is someone who sins publicly, and then he must be rebuked publicly; and someone who sins secretly, and then he must be rebuked secretly; and this is clear, because Augustine says that if he has sinned with you alone knowing it, "rebuke him between you and him alone." "But if he hears you, you have gained your brother." To what end does he say this? On account of three things. That you may know for what end you ought to rebuke: because if you rebuke for your own sake, you accomplish nothing, since where the amends sought is private, the correction is not meritorious; but if for God's sake, then it avails. Again, this is what you ought to intend, namely to instill the rebuke and teaching into the mind of the brother. Again, someone might say that it would not be just to lose one's brother. But if that were so, he would not have said, "you have gained your brother." Again, "gained," because he is a fellow-member of yours: and just as a member has fellow-feeling with a member, so too you with your brother. Again, "gained," because you gain salvation for yourself; James 4:11: "he who judges his brother detracts from the law, and judges the law"; hence in the same epistle, 5:20: "he who causes a sinner to be converted from the error of his way saves his soul from death, and covers a multitude of sins." "But if he does not hear you, take with you one or two." Here he brings in the testimony, "take one or two," etc. Deuteronomy 19:15: "in the mouth of two or three witnesses let every word stand." But here is a question: why does he not bring in witnesses right away? It must be said that conscience must be cleansed in such a way that reputation is not harmed: hence if he can correct him first and by himself, well and good; if not, then let him call in witnesses. And Jerome says that first one, and afterward two. And why? That they may be witnesses of the correction made, because if he proceeds further, it is not to be imputed to you. Jerome says it is also for another purpose, namely so that he may be convicted of the sin: because some are so obstinate that they do not acknowledge it, and therefore you ought to bring witnesses, so as to convict him of the deed. Or perhaps he will repeat the injury. Or, according to Augustine, to convict him. But against this seems to be what Augustine says, that before showing it to two, he ought to show it to the superior, and this is to show it to the Church. Therefore it seems to invert the order. I say that it can be shown to the prelate either in a judicial order, or as to a private person. Augustine means, therefore, that it ought to be shown to the superior first as to a private person, so that, as a private person, he may take pains toward the correction. Hence he says, "if he does not hear them, tell it to the Church." Here the denunciation is set forth. And first he denounces; second the sentence is set forth; third the efficacy. The second at "but if he does not hear the Church," etc.; the third at "Amen I say to you," etc. He says, "but if he does not hear them, tell it to the Church," that is, to the whole multitude, that he may be confounded, so that he who was unwilling to be rebuked without confusion may be rebuked with confusion. For there is a shame that brings sin, and there is a shame that brings glory and grace, Ecclesiasticus 4:25. Or "to the Church," that is, to the judges, that he may be corrected; Deuteronomy 21:18: "if a man has a stubborn and defiant son who will not hear the command of his father and mother, and, having been disciplined, refuses to obey, they shall seize him and bring him to the elders of that city, and to the gate of judgment," etc. Then the penalty is added: "if he does not hear the Church, let him be to you as a heathen and a publican." Heathens are the gentiles and unbelievers; publicans are those who collect the tribute, who are public sinners. Hence, as if set apart, let them be excommunicated by the sentence of the Church, because they did not hear the Church. Hence for contumacy alone a man can be excommunicated. "Amen I say to you," etc. Here the efficacy of this sentence is set forth. For someone might say: what do I care if it is told to the Church, and I am excommunicated? Therefore he shows this efficacy: "Amen I say to you, whatever you shall bind on earth shall be bound also in heaven; and whatever you shall loose on earth shall be loosed also in heaven." Above, these things were said to Peter; but here it is said to the whole Church. And he is said to bind, either because he does not absolve, or because he excommunicates. Origen says that here he says "in heaven," whereas when he spoke to Peter, he said "in the heavens," to designate that Peter has universal power. But here he says "in heaven," because their power is not universal, but limited to some place, since he gave universal power to Peter. "Again I say to you," etc. Here he sets forth the efficacy of prayer. And first he does this; second he gives the reason, at "for where there are two," etc. He says, "again I say to you," etc. But you can object, because we ask for many things which we do not obtain. This happens, first, on account of the unworthiness of those asking; hence he says "two of you," namely, who live according to the Gospel. James 4:3: "you ask, and do not receive, because you ask wrongly." Again, it happens because they do not agree together, because they do not have the bond of peace: for it is impossible that the prayers of many not be heard, if out of many prayers there is made, as it were, one; 2 Corinthians 1:11: "so that, from the persons of the many faces, thanks may be given by many on our behalf for the gift that is in us." Again, because they ask for certain things which are not expedient for them unto salvation: for the petition ought to be about something useful; below, 20:22: "you do not know what you ask." "It shall be done for them by my Father," who is in heaven, that is, in the heights: or "in heaven," that is, in us. "For where there are two or three gathered together in my name, there am I in the midst of them"; in a gathering of the holy, not of the earthly. Psalm 110:1: "great are the works of the Lord, in the council of the just and in the congregation." "Where therefore two or three." Charity is not in one, but in many; hence 1 John 4:16: "he who abides in charity abides in God, and God in him." Therefore, "I am in the midst of them." "Then Peter, coming to him, said: Lord, how often shall my brother sin against me, and I forgive him?" Above he taught in what order forgiveness is to be given, namely after correction and amends; here he deals with the number of times forgiveness is to be given. First, therefore, Peter's question is set forth; second, Christ's response; third, a comparison is applied. The second at "Jesus says to him," etc.; the third at "the kingdom of heaven is likened." He says, therefore, "then, coming." "Then," namely, having heard this saying, "if your brother sins against you," etc., Peter was then moved to ask whether he should forgive once or many times, and he said, "how often shall my brother sin against me," etc., "shall I forgive up to seven times," as if to say: up to seven times is a matter of weakness, but more is a matter of malice. Therefore he asked whether he should forgive up to seven times. Again, he knew that which is said in 4 Kings 5:10, that Elisha commanded Naaman to wash himself seven times in the Jordan; therefore he thought that he ought to forgive seven times. Jesus says to him: "I do not say to you seven times, but seventy times seven." In one way this can be taken, what he says "seven times," cumulatively, so that the sense is: not seven times, but seventy times. Or it can be taken multiplicatively, so that seventy times seven; and thus Jerome expounds it. According to the first exposition, which is Augustine's, it is given to be understood that we ought to forgive entirely, just as Christ forgave everything. Colossians 3:13: "forgiving one another, if anyone has a complaint against another; even as the Lord has forgiven you, so also do you." Or it can be said that a finite number is put for an infinite one, as in the Psalms: "the word which he commanded unto a thousand generations." According to Jerome, the cause is the same; yet a reason for the number is added. For by six perfection is signified; by the hundred, which is multiplied by ten, the Decalogue is signified. The first number that departs from ten is the eleventh. And because by six the totality is signified, therefore the totality of sins is signified; as if he were to say: whatever things your brother has sinned against you, forgive him. Hence, according to Jerome, it seems that he means to say that one can forgive more than the brother could possibly offend.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Therefore is the kingdom of heaven,.... The Gospel church state, or the church of Christ under the Gospel dispensation, and the methods of God's dealings in it; likened unto a certain king: or "a man", "a king", pointing either to Christ, the king Messiah, who is King of kings, and Lord of lords, the King of saints and churches; who, as God, has a natural kingdom of providence, and as man and Mediator, a kingdom of grace; and will have a more visibly glorious one, both in this world and in the other; or rather, the Father of Christ, as appears from the application of the parable, in Mat 18:35, who is the living God, and everlasting King: whose is the kingdom of nature, grace, and glory: which would take account of his servants; not all mankind, though these are all in a sense his servants, and accountable to him; nor only ministers of the Gospel, who are so in an eminent and peculiar sense, and must give an account to God of their time and talents, and souls committed to them; but all that bear the Christian name, that are professors of religion, that are either really or nominally the subjects and servants of God. These, it is sometimes the will and pleasure of God, to "take account of": not of their persons, or number, but of their conduct and behaviour; which, as it will be more fully done at death, or at judgment, so sometimes is taken in this life: God sometimes calls, and brings, professors of religion to an account, and reckons with them by afflictive dispensations of providence; when he puts them upon reflecting how they have spent their time, made use of their talents and gifts, and have behaved in their families, and in the world, and church; or by dealing roundly with men's consciences, awakening and convincing them of their sins, of omission and commission, which seems to be intended here.”
Source
1849
A.D.
1774–1849
“There am I in the midst of them. This is understood of such assemblies only, as are gathered in the name and authority of Christ; and in unity of the Church of Christ. (St. Cyprian, de Unitate Ecclesiĉ.) (Challoner) — St. Chrysostom, Theophylactus, and Euthymius explain the words in his name, thus, assembled by authority received from Christ, in the manner appointed by him, or for his sake, and seeking nothing by his glory. Hence we may see what confidence we may place in an œcumenical council lawfully assembled. (Tirinus) (St. Gregory, lib. vii. Regist. Epist. cxii.)”
Source
1871
A.D.
1871
“For where two or three are gathered together in my name--or "unto my name." there am I in the midst of them--On this passage--so full of sublime encouragement to Christian union in action and prayer--observe, first, the connection in which it stands. Our Lord had been speaking of church meetings before which the obstinate perversity of a brother was in the last resort to be brought, and whose decision was to be final--such honor does the Lord of the Church put upon its lawful assemblies. But not these assemblies only does He deign to countenance and honor. For even two uniting to bring any matter before Him shall find that they are not alone, for My Father is with them, says Jesus. Next, observe the premium here put upon union in prayer. As this cannot exist with fewer than two, so by letting it down so low as that number, He gives the utmost conceivable encouragement to union in this exercise. But what kind of union? Not an agreement merely to pray in concert, but to pray for some definite thing. "As touching anything which they shall ask," says our Lord--anything they shall agree to ask in concert. At the same time, it is plain He had certain things at that moment in His eye, as most fitting and needful subjects for such concerted prayer. The Twelve had been "falling out by the way" about the miserable question of precedence in their Master's kingdom, and this, as it stirred their corruptions, had given rise--or at least was in danger of giving rise--to "offenses" perilous to their souls. The Lord Himself had been directing them how to deal with one another about such matters. "But now shows He unto them a more excellent way." Let them bring all such matters--yea, and everything whatsoever by which either their own loving relationship to each other, or the good of His kingdom at large, might be affected--to their Father in heaven; and if they be but agreed in petitioning Him about that thing, it shall be done for them of His Father which is in heaven. But further, it is not merely union in prayer for the same thing--for that might be with very jarring ideas of the thing to be desired--but it is to symphonious prayer, the prayer by kindred spirits, members of one family, servants of one Lord, constrained by the same love, fighting under one banner, cheered by assurances of the same victory; a living and loving union, whose voice in the divine ear is as the sound of many waters. Accordingly, what they ask "on earth" is done for them, says Jesus, "of My Father which is in heaven." Not for nothing does He say, "of MY FATHER"--not "YOUR FATHER"; as is evident from what follows: "For where two or three are gathered together unto My name"--the "My" is emphatic, "there am I in the midst of them." As His name would prove a spell to draw together many clusters of His dear disciples, so if there should be but two or three, that will attract Himself down into the midst of them; and related as He is to both the parties, the petitioners and the Petitioned--to the one on earth by the tie of His assumed flesh, and to the other in heaven by the tie of His eternal Spirit--their symphonious prayers on earth would thrill upward through Him to heaven, be carried by Him into the holiest of all, and so reach the Throne. Thus will He be the living Conductor of the prayer upward, and the answer downward. Parable of the Unmerciful Debtor (Mat 18:21-35).”
Source

Undated

date unknown
date
unknown
Glossa Ordinaria Medieval
“(ap. Anselm.) But He holds out a ratification not only of sentences of excommunication, but of every petition which is offered by men holding together in the unity of the Church; for He adds, Again I say unto you, that if two of you shall agree upon earth, whether in admitting a penitent, or casting out a forward person, touching any thing which they shall ask, any thing, that is, that is not against the unity of the Church, it shall be done for them by my Father which is in heaven. By saying, which is in heaven, He points Him out as above all, and therefore able to fulfil all that shall be asked of Him. Or, He is in the heavens, that is, with saints, proof enough that whatever worthy thing they shall ask shall be done unto them, because they have with them Him of whom they ask. For this cause is the sentence of those that agree together ratified, because God dwells in them, For where two or three are gathered together in my name, there am I in the midst of them.”
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.