The interpretation timeline
Romans 8:27 Douay-Rheims

And he that searcheth the hearts, knoweth what the Spirit desireth; because he asketh for the saints according to God.

A.D. 407 – 1832 5 witnesses

Patristic

before A.D. 750
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“"But He that searcheth the hearts." You see that it is not about the Comforter that he is speaking, but about the spiritual heart. Since if this were not so, he ought to have said, "He that searcheth" the Spirit. But that thou mayest learn that the language is meant of a spiritual man, who has the gift of prayer, he proceeds, "And he that searcheth the hearts knoweth what is the mind of the Spirit," that is, of the spiritual man. "Because he maketh intercession for the saints according to the will of God." Not (he means) that he informs God as if ignorant, but this is done that we may learn to pray for proper things, and to ask of God what is pleasing to Him. For this is what the "according to God" is. And so this was with a view to solace those that came to Him, and to yield them excellent instruction. For He that furnished the gifts, and gave besides blessings without number, was the Comforter. Hence it says, "all these things worketh one and the self-same Spirit." And it is for our instruction that this takes place, and to show the love of the Spirit, it condescendeth even to this. And it is from this that the person praying getteth heard, because the prayer is made "according to the will of God." You see from how many points he instructs them in the love that was shown them and the honor that was done them. And what is there that God hath not done for us? The world He hath made corruptible for us, and again for us incorruptible. He suffered His Prophets to be ill-treated for our sake, sent them into captivity for us, let them fall into the furnace, and undergo ills without number. Nay, He made them prophets for us, and the Apostles also He made for us. He gave up for us His Only-Begotten, He punisheth the devil for us, He hath seated us on the Right Hand, He was reproached for us. "For the reproaches of them that reproached thee," it says, "fell upon me."”
Source
523
A.D.
c. A.D. 450–523
“You see that all the good promptings which bring us to repentance result from the activity of the Spirit, and pure prayer, which brings all these good promptings to completion, is also stirred up in our soul as the result of the Spirit's activity. He too, in a hidden way, initially arouses us to groans at the memory of our sins.”
Source

Scholastic

c. 1100 – 1500
1273
A.D.
Thomas Aquinas Catholic
1225–1274
“Above, the Apostle showed the excellence of future glory from the expectation of the creature; now he shows the same thing from the expectation of the apostles. But that which is awaited so anxiously by great men cannot be a small thing. And concerning this he does two things. First he sets forth what he intends; second he proves what he has proposed, at the words "for we are saved by hope," and so on. Concerning the first he does three things. First he sets forth the dignity of those who wait, when he says "not only that"—namely the creature—"awaits the glory of the sons of God, but we ourselves also"—namely the apostles—"having the firstfruits of the Spirit"; because, namely, the apostles had the Holy Spirit both earlier in time and more abundantly than the rest, just as also among the fruits of the earth that which first arrives at maturity is richer and more acceptable. Jeremiah 2:3: "Israel is holy to the Lord, the firstfruits of his increase." Hebrews 12:23: "You have come to the church of the firstborn, who are written in the heavens." From this it is clear that the apostles are to be preferred to all other saints, by whatever prerogative they may shine forth—whether of virginity, or of doctrine, or of martyrdom—inasmuch as they had the Holy Spirit more abundantly. But someone may say that certain other saints endured greater torments, and greater austerities for Christ's sake, than the apostles. But it must be known that the magnitude of merit, principally and with respect to the essential reward, is measured according to charity. For the essential reward consists in the joy that is had of God. But it is manifest that those who love more will rejoice more in God. Hence the Lord also promises that blessed vision to his beloved, saying, John 14:21: "If anyone loves me, he shall be loved by my Father, and I will love him, and will manifest myself to him." But according to the quantity of works, a man merits the accidental reward, which is the joy over such works. The apostles, therefore, did those works which they did out of a greater charity, from which they had a heart ready to do many greater things, had it been opportune. But if someone should say: a person can strive so much that he will have charity equal to the apostles', it must be said that a man's charity is not from himself, but from the grace of God, which is given to each according to the measure of the gift of Christ, as is said in Ephesians 4:7. But he gives to each one grace proportioned to that for which he is chosen, just as to the man Christ was given the most excellent grace, because he was chosen for this: that his nature should be assumed into the unity of the divine person; and after him blessed Mary had the greatest fullness of grace, who was chosen for this: that she should be the mother of Christ. But among the rest, the apostles were chosen to a greater dignity, namely that, receiving immediately from Christ himself, they should hand on to others those things which pertain to salvation, and thus the Church should in a certain way be founded in them, according to Revelation 21:14: "The wall had twelve foundations, and on them were written the names of the apostles"; and therefore it is said in 1 Corinthians 12:28: "God has placed in the Church first indeed apostles." And therefore God bestowed on them a more abundant grace beyond the rest. Second, he sets forth the anxiety of the expectation when he says, "and we ourselves groan within ourselves." This groaning indeed designates the affliction arising from the delay of a thing awaited with great desire, according to Proverbs 13:12: "Hope that is deferred afflicts the soul." Psalm 6:6: "I have labored in my groaning." But this groaning is not so much exterior as interior, both because it proceeds from the interior affection of the heart, and because it is on account of interior goods. Hence he significantly says "within ourselves." Lamentations 1:22: "Many are my groanings." Third, he sets forth the thing awaited, saying "awaiting the adoption of the sons of God," that is, the completion of this adoption. For this adoption was begun through the Holy Spirit justifying the soul. Above, in the same chapter: "You have received the spirit of adoption of sons." But it will be consummated through the glorification of the body itself. Hence above, 5:2: "We glory in the hope of the glory of the sons of God." And this is what he adds, "the redemption of our body," namely that just as our spirit has been redeemed from sin, so our body may be redeemed from corruption and death. Hosea 13:41: "I will redeem them from death." Philippians 3:21: "He will reform the body of our lowliness." Then, when he says "for by hope," etc., he proves what he had said by this reasoning: hope concerns those things which are not seen as present, but are awaited in the future. But we have been made saved through hope; therefore we await in the future the completion of salvation. First, then, he sets forth the minor premise, saying: "for we"—the apostles and the rest of the faithful—"have been made saved by hope," because, namely, we have the hope of our salvation. 1 Peter 1:3: "He has regenerated us unto a living hope." Psalm 61:9: "Trust in him, all you congregation of the people." Second, he sets forth the major premise, saying, "but hope"—that is, the thing hoped for—"which is seen," as it were possessed in the present, "is not hope"—that is, it is not a thing hoped for, but a thing possessed. For hope is the expectation of what is future. Zephaniah 3:8: "Wait for me in the day of my resurrection that is to come." Third, he sets forth the proof of the major premise, saying, "for what a man sees, why"—that is, for what reason—"does he hope for it?" As if he were saying: hope implies a movement of the soul tending toward something not yet possessed. But when something is already possessed, it is not necessary that one be moved toward it. And it must be noted that, because hope in a certain way arises from faith, he attributes to hope that work which belongs to faith, namely, to be concerned with things not seen, according to Hebrews 11:1: "Faith is the evidence of things that do not appear." Fourth, he sets forth the conclusion, saying, "but if we hope for what we do not see, it follows that we wait for it through patience." Hence it must be noted that, properly speaking, patience implies the toleration of tribulations with a certain equanimity. Below, 12:12: "Patient in tribulation." But because the delay of a good has a certain character of evil, hence it is that also the prolonged expectation of absent goods, accompanied by tranquility of soul, is attributed to patience; but this belongs most especially to longanimity, according to James 5:7: "Be patient, brothers, until the coming of the Lord." But patience is here taken in both ways, because the apostles awaited glory with equanimity, both amid delay and amid tribulation. Then, when he says "likewise also," etc., he shows how we are helped by the Holy Spirit in the defects of the present life. And first, as to the completion of desires; second, as to the direction of external events, at the words "and we know," etc. Concerning the first he does two things. First he sets forth what he intends; second he makes clear what he has proposed, at the words "for what we should pray for," etc. He says therefore first: it has been said that our mortal bodies will be brought to life through the Holy Spirit, when our infirmity will be taken away from us; likewise also, even in the state of this present life, in which we are still subject to infirmity, the Spirit helps our infirmity, even if he does not take it away entirely. Ezekiel 3:14: "The spirit also lifted me up, and took me; and I went away bitter in the indignation of my spirit"; as though the infirmity had not yet entirely ceased, "for the hand of the Lord was with me, strengthening me." And in this the spirit took me up. Matthew 26:41: "The spirit indeed is willing, but the flesh is weak." Then, when he says "for what we should pray for," etc., he makes clear what he had said. And first he shows the necessity of the Spirit's help, which pertains to the infirmity of the present life; second he shows the manner of the help, at the words "but the Spirit himself," etc.; third he shows the efficacy of the help, at the words "but he who searches." He says therefore first: rightly do I say that the Spirit helps our infirmity; for in this we suffer infirmity, that we do not know what we should pray for, as we ought. Job 3:23: "To a man whose way is hidden, and whom God has surrounded with darkness." And it must be considered that the Apostle says we do not know two things, namely, what we should ask for in praying, and the manner in which we ought to ask; but each of these seems to be false. For, as to the first, we know what we should pray for: because the Lord taught us this, Matthew 6:9: "Hallowed be thy name," and so on. But it must be said that in general indeed we can know what we should suitably pray for, but in particular we cannot know this. First indeed, because if we desire to do some work of virtue, which is to fulfill the will of God, as in heaven so on earth, it can happen that this work of virtue is not fitting for this or that person: just as for someone who can profitably advance in action, the quiet of contemplation is not expedient, and conversely, as Gregory says in the Moralia on that verse of Job 5:26: "Entering into the grave in abundance." Hence it is said, Proverbs 14:12: "There is a way which seems just to a man, but its ends lead to death." Second, someone desires some temporal good for the sustenance of life, which is to ask for daily bread, which nevertheless turns for him into a danger of death. For many have perished on account of riches. Ecclesiastes 5:12: "Riches kept to the hurt of their owner." Third, someone desires to be freed from some trouble of temptation, which nevertheless serves for him as a safeguard of humility: just as Paul asked that the sting be removed from him, which nevertheless had been given to him lest the greatness of his revelations should exalt him, as is said in 2 Corinthians 12:7. Likewise also it seems that we know how we ought to pray, according to James 1:6: "Let him ask in faith, nothing wavering." And to this it must be said that in general we can know this, but as to the particular motion of our heart we cannot discern it thoroughly—for instance, whether we ask something out of anger, or out of zeal for justice. Hence also in Matthew 20:20, the petition of the sons of Zebedee was rejected, because although they seemed to be asking for a share in the divine glory, nevertheless their petition proceeded from a certain vainglory or pride. Then, when he says "but he himself," etc., he sets forth the manner of the Holy Spirit's help, saying that the Spirit himself asks for us with unspeakable groanings. This indeed seems to lend support to the error of Arius and Macedonius, who held that the Holy Spirit is a creature and less than the Father and the Son; for to ask is the mark of one who is lesser. But if from the fact that he says he "asks," we should understand him to be a passible creature and less than the Father, it follows likewise that from the fact that he says he asks "with groanings," we should understand him to be a passible creature lacking beatitude—which no heretic ever said. For groaning arises from sorrow, which pertains to misery. And therefore "he asks" must be explained as meaning: he makes us ask, just as also in Genesis 22:12: "Now I know that you fear the Lord," that is, "I have made known." But the Holy Spirit makes us ask, inasmuch as he causes right desires in us. For asking is a certain unfolding of desires. But right desires proceed from the love of charity, which, namely, he produces in us. Above, 5:5: "The charity of God is poured forth in our hearts through the Holy Spirit, who has been given to us." But with the Holy Spirit directing and stirring up our heart, our desires cannot be other than useful to us—Isaiah 48:17: "I am the Lord who teaches you profitable things"—and therefore he adds "for us." But of that which we desire greatly and eagerly ask for, we suffer the delay with sorrow and groanings; and therefore he adds "with groanings," which, namely, he causes in our heart, inasmuch as he makes us desire heavenly things, which are deferred to the soul. This is the groaning of the dove, which the Holy Spirit produces in us. Nahum 2:7: "They led her away, moaning like doves." But he says "unspeakable": either because they are on account of an unspeakable thing, namely heavenly glory—2 Corinthians 12:4: "He heard secret words, which it is not lawful for a man to speak"—or because these very movements of the heart cannot be sufficiently expressed in words, insofar as they proceed from the Holy Spirit. Job 38:37: "Who shall declare the order of the heavens?" Then, when he says "but he who searches," etc., he shows the efficacy of the help by which the Holy Spirit helps us, saying, "but he who searches the hearts"—that is, God, to whom it is proper to search the hearts. Psalm 7:10: "God, who searches the hearts and reins." But God is said to search the hearts, not because he comes to know the hidden things of the heart by inquiring, but because he manifestly knows the things that lie hidden in the heart. Zephaniah 1:12: "I will search Jerusalem with lamps." God, I say, searching the hearts, "knows"—that is, approves, according to 2 Timothy 2:19: "The Lord knows who are his"—"what the Spirit desires," that is, what he makes us desire. Psalm 37:9: "Lord, all my desire is before thee." But the reason the desires of the Spirit, which the Holy Spirit produces in the saints, are acceptable to God, is that "he asks for the saints"—that is, he makes them ask—"according to God," that is, in accordance with what agrees with the divine good pleasure—Proverbs 11:23: "The desire of the just is all good"—in imitation of which the Lord said to the Father, Matthew 26:39: "Not as I will, but as thou wilt."”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“And he that searcheth the hearts,.... This is peculiar to God, and a "periphrasis" of him; angels, neither good nor bad, can search into the hearts of men; one man cannot know the heart of another, nor any man fully know his own; this is the prerogative of God: and he knoweth what is the mind of the Spirit; not the spirit of men, but of God: that affectionate desire and meaning of the Spirit of God, in the unalterable groans of the saints; he knows the wise meaning there is in them, for so may signify, and is opposed to the carnal mind, or wisdom of the flesh, which desires foolish things. The searcher of hearts knows this, not barely by his omniscience, but he regards it, approves of it, attends, and gives an answer to it; which is no small encouragement to pray, though it be but with sighs and groans unutterable; since the omniscient God understands, and respects such kind of prayer: and the reason is, because he, the Spirit of God, maketh intercession for the saints, according to the will of God; the persons for whom he intercedes are saints: to whom Christ is made sanctification; who are called to be saints; are sanctified by the Spirit of God, and walk after him: now such are the objects of God's delight, they are chosen by him, preserved in Christ, and have his righteousness imputed to them; to these he has made known his Gospel, has given his grace, and will at last the inheritance; so that intercession made for such will certainly be regarded: it may be rendered, "he maketh intercession for holy things according to God"; for spiritual blessings, divine favours, things that belong to God; or divine things, which are agreeably to his nature and will: and since it is the Holy Spirit that makes intercession, and the persons are holy for whom he makes it, and this is made for holy things, and all according to the will of God, which the Spirit of God must fully know, saints may be confident of the prevalence and success of such intercession.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“He maketh intercession for the saints - The word εντυγχανω signifies to apply one's self to a person in behalf of another; to intercede or negotiate for. Our Lord makes intercession for us, by negotiating and managing, as our friend and agent, all the affairs pertaining to our salvation. And the Spirit of God makes intercession for the saints, not by supplication to God on their behalf, but by directing and qualifying their supplications in a proper manner, by his agency and influence upon their hearts; which, according to the Gospel scheme, is the peculiar work and office of the Holy Spirit. See Taylor. According to the will of God - Κατα Θεον· According to the mind, intention, or design of God. And thus the prayers which we offer up, and the desires which subsist in the unutterable groanings, are all such as are pleasing in the sight of God. So that God, whose is the Spirit, and who is acquainted with the mind of the Spirit, knows what he means when he leads the saints to express themselves in words, desires, groans, sighs, or tears: in each God reads the language of the Holy Ghost, and prepares the answer according to the request. From all this we learn that a fluency in prayer is not essential to praying: a man may pray most powerfully in the estimation of God, who is not able to utter even one word. The unutterable groan is big with meaning, and God understands it, because it contains the language of his own Spirit. Some desires are too mighty to be expressed; there is no language expressive enough to give them proper form and distinct vocal sound: such desires show that they came from God; and as they came from him, so they express what God is disposed to do, and what he has purposed to do. This is a matter of great encouragement to all those who are agonizing to enter in at the strait gate.”
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.