The interpretation timeline
1 Corinthians 10:18 Douay-Rheims

Behold Israel according to the flesh: are not they, that eat of the sacrifices, partakers of the altar?

A.D. 407 – 1871 6 witnesses

Patristic

before A.D. 750
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“"Behold Israel after the flesh: have not they which eat the sacrifices communion with the altar?" Again, from the old covenant he leads them unto this point also. For because they were far beneath the greatness of the things which had been spoken, he persuades them both from former things and from those to which they were accustomed. And he says well, "according to the flesh," as though they themselves were according to the Spirit. And what he says is of this nature: "even from persons of the grossest sort ye may be instructed that they who eat the sacrifices, have communion with the altar." Dost thou see how he intimates that they who seemed to be perfect have not perfect knowledge, if they know not even this, that the result of these sacrifices to many oftentimes is a certain communion and friendship with devils, the practice drawing them on by degrees? For if among men the fellowship of salt and the table becomes an occasion and token of friendship, it is possible that this may happen also in the case of devils. But do thou, I pray, consider, how with regard to the Jews he said not, "they are partakers with God," but, "they have communion with the altar;" for what was placed thereon was burnt: but in respect to the Body of Christ, not so. But how? It is "a Communion of the Lord's Body." For not with the altar, but with Christ Himself, do we have communion.”
Source

Scholastic

c. 1100 – 1500
1270
A.D.
1225–1276
“Above he warned them to abstain from eating things sacrificed to idols, first out of fear of a like punishment, second from the communion of the altar; here, thirdly, he warns them to the same by the likeness of the legal sacrifice. In this, first he arouses attention; second he shows his proposition, at "are not they that eat of the sacrifices." He says therefore "behold." This is read in two ways. In one way concerning the sacrifices of the Jews, in another way concerning the rite of the gentiles. In the first way, this word which he says, "Israel," is of the accusative case; in the other way, of the vocative. In the first way thus, as if he were to say: we, being many, are one body, who partake of one bread and of one cup. And this is plain through this likeness: "behold Israel according to the flesh" — supply, walking, that is, serving carnal sacrifices. He says this to distinguish it from Israel according to the spirit. Concerning both, Rom. 2:28: "for not he who is openly a Jew," et cetera. "Are not they that eat of the sacrifices" — the legal ones — "partakers of the altar" — the legal one? Just as they who eat the flesh and blood of Christ are partakers of his body. In the second way it is read thus: "behold, O Israel" — O you who are Israel, seeing spiritually, namely God; behold, I say, "the things that are according to the flesh," that is, in the carnal rite of idolatry. "Are not they that eat of the sacrifices" — namely, those immolated to idols — "partakers of the altar" — of demons and of idols? As if he were to say: yes. His reasoning therefore is this: they who eat the sacrifices offered to the altar are partakers of the altar. By like reasoning, they who eat the sacrifices immolated to idols are partakers of idols, or of demons. Then, when he says "what therefore do I say?," etc. — above he set down the warning to beware of eating things sacrificed to idols; here he sets down the cause of the warning. He sets down four causes why they ought to abstain from things sacrificed to idols: first, to avoid the company of the demon; second, to avoid exclusion from the sacred communion, at "because you cannot drink the cup of the Lord," etc.; third, to avoid the indignation of God, at "do we provoke the Lord to jealousy?," etc.; fourth, on account of the injury of the brethren, at "all things are lawful to me," et cetera. In the first, first he shows by this that he does not say this because he reckons an idol, or a thing sacrificed to an idol, to be of any power; second, that it is rather for this reason, because it is immolated to demons, at "but the things which they sacrifice," etc.; third, that he does not wish them to be companions of demons, at "but I would not that you should be made partakers," et cetera. He says therefore: "what then?" As if he were to say: I warn you to beware of things sacrificed to idols. What then do I say? That is, what do I seem to be saying by this warning? Is it this — supply, that that which is sacrificed to idols is something, or of some power, so as to harm, or that an idol is something worthy of veneration? As if he were to say: no. Ps. 134:17: "for neither is there any spirit in their mouth." But I say this rather, that "the things which the gentiles sacrifice," they sacrifice to an idol, to a demon, "and not to God." Ps. 95:5: "all the gods of the gentiles are demons." Deut. 32:17: "they sacrificed to demons, and not to God." Then, when he says "but I would not that you should be made," etc., he shows that he does not wish them to be made companions of demons, which would happen if they shared in the table of idols. And this is what he says: "but I would not that you," who are the faithful, "should be made companions of demons" — namely, by eating of those things which are sacrificed to idols. 2 Cor. 6:14 f.: "what fellowship has light with darkness, or what agreement has Christ with Belial?" Then, when he says "you cannot drink the cup," et cetera. Behold the second reason why one must abstain from things sacrificed to idols, which is this: everything that excludes from the communion of the body and blood of Christ is to be avoided; the eating of things sacrificed to idols is of this kind; therefore it is to be avoided. First, therefore, he shows that eating of this kind excludes from the communion of the blood of Christ; second, that it also excludes from the communion of the body of Christ, at "you cannot be partakers of the table of the Lord," et cetera. He says therefore "you cannot," etc., as if he were to say: I do not wish you to be made companions of demons. Now he says this for this reason: because "you cannot drink the cup of the Lord" — by a spiritual drinking, not a merely sacramental one; Ps. 115:13: "I will take the chalice of salvation" — "and the cup of demons," at the same time: and this as regards the sacrament of the blood. "You cannot be partakers of the table of the Lord," as regards the sacrament of the body, "and of the table of demons." Matt. 6:24: "no man can serve two masters." Behold therefore a fruitful cup, because precious to drink spiritually, because pure and clean in a special way as the Lord's, because it is not given usefully to the unclean. Likewise it can be said of the table. Then, when he says "do we provoke the Lord to jealousy?," etc., behold the third reason, which is this: everything that provokes the wrath of God is to be avoided; the eating of things sacrificed to idols is of this kind, therefore it is to be avoided. First, therefore, he shows that God is provoked by such eating; second, that it is foolish to provoke him, at "are we stronger than he?," et cetera. He says therefore "do we provoke to jealousy," that is, do we wish to provoke the Lord to wrath, by eating things sacrificed to idols? Or thus, "do we provoke the Lord to jealousy," that is, do we envy him, so that we do this as it were in contempt of him? Deut. 32:16: "they provoked him with gods." "Are we" — as if he were to say: we ought not to provoke him. "Are we stronger than he?" As if he were to say: no. Job 9:19: "if strength be sought, he is most mighty." For it is foolish to provoke one stronger than oneself. It should be noted, concerning that phrase "but I would not that you should be made companions," that there is a good fellowship and an evil one, and each is fourfold. There is, then, a good fellowship: first, of the divine persons, concerning which 1 John 1:3: "that we may have fellowship with God, and our fellowship be with the Father and with his Son Jesus Christ." And this the highest delight requires, because the possession of nothing is delightful without a companion. Second, of the holy angels, concerning which Tob. 5:27: "for I believe that a good angel of God accompanies him," and this the dignity of man requires. Jerome: "great is the dignity of souls," et cetera. Third, of just men, concerning which Gal. 2:9: "James and John gave to me and to Barnabas the right hands of fellowship," and this our own advantage requires. Eccles. 4:9: "two are better," et cetera. Fourth, of the blessed, concerning which Apoc. 1:9: "I John, your companion and brother in tribulation and in the kingdom," and this a common happiness requires; for if we are companions of the suffering, we shall also be companions of the consolation, 2 Cor. 1:7. The evil fellowship is likewise fourfold: first, on the part of the wicked, concerning which Isa. 1:23: "your princes are faithless, companions of thieves." This is the fellowship of Herod and Pilate in the crucifixion of Christ. Second, of hypocrites, concerning which Job 30:29: "I was a brother to dragons, and a companion to ostriches," which seems to have wings and cannot fly. This is the fellowship of the fox and the wolf. Third, of demons, concerning which Job 18:15: "let there dwell in his tabernacle the companions of him that is not." This is the fellowship of the cat and the mouse, of the executioner and the ox. Fourth, of the damned, concerning which 2 Cor. 6:14: "what fellowship has light with darkness?" This is the fellowship of those imprisoned in the fire. Then, when he says "all things are lawful to me," etc., the fourth reason is set down, which is this: everything that harms the salvation of one's neighbors is to be avoided; but the eating of things sacrificed to idols is of this kind, therefore it is to be avoided. First he shows that such eating does not profit the one who eats; second, that it harms another, at "all things are lawful to me," et cetera. He says therefore "all things are lawful to me," etc., as if he were to say: if I should say that those sin who eat things sacrificed to idols, I do not for that reason say that foods are unlawful in themselves, because all things that pertain to food are lawful to me. Or: "and if all things are lawful to me, yet not all things are expedient," that is, they help me in my course. Similarly above, 6:12. "All things are lawful to me," that is, even if all things were lawful to me, yet not all things edify one's neighbors, but those things which belong to charity; above, 8:1: "knowledge puffs up, charity edifies." And because not all things edify, "let no one seek only what is his own," for charity "seeks not the things that are her own," below, 13:5, "but that which is another's," that is, that which profits another. But alas — it is said in Phil. 2:21: "all seek the things that are their own." The apostle, therefore, is to be heeded, who both teaches the truth and counsels the good. He teaches a twofold truth, namely, of what is expedient for oneself, because "all things are lawful, but not all are expedient," and of edification for others, because "all things are lawful, but not all things edify." He counsels a twofold good, namely, of what is expedient for oneself, "let no one seek only what is his own," and of edification for others, "but that which is another's."”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Behold Israel after the flesh,.... So the apostle calls them, to distinguish them from the Israel of God, the spiritual Israel, whether Jews or Gentiles; who are born again, believe in the true Messiah, worship God in a spiritual manner, rejoice in Christ Jesus, and have no confidence in fleshly things; but these were the descendants of Jacob or Israel by carnal generation, were carnal men, in the flesh, in a state of unregeneracy, and were employed in a carnal worship, in the observance of carnal commandments and ordinances; these the apostle directs to, to see, consider, and take notice of what they were doing; from whence some instruction might be taken, for the further clearing of the present point: are not they which eat of the sacrifices partakers of the altar? yes, they are. The priests and Levites who waited at the altar, and ministered about holy things there, who brought the sacrifices and laid them upon the altar of the burnt offerings, where the altar consumed and devoured one part by fire, and that which was left they ate among themselves; and so as they had communion with one another in eating, they partook of the altar, of the things, or sacrifices of the altar, and showed themselves to be of the Jewish religion, and professed and declared that they worshipped the God of Israel, and would be thought to have communion with him in so doing; in like manner, such who eat of things sacrificed to idols, declared themselves to be idolaters, to be of the Pagan religion, to be worshippers of idols, and to have fellowship with them.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Behold Israel after the flesh - The Jews not yet converted to Christianity: the latter being Israel after the Spirit. As the design of the apostle was to withdraw his converts at Corinth from all temptations to idolatry, he produces two examples to show the propriety of his endeavors. 1. All who join together in celebrating the Lord's Supper, and are partakers of that one bread, give proof by this that they are Christians, and have fellowship with Christ. 2. All the Israelites who offer sacrifice, and partake of those sacrifices, give proof thereby that they are Jews, and are in fellowship with the object of their worship: so they who join in idol festivals, and eat things which have been offered to idols, give proof that they are in communion with those idolaters, and that they have fellowship with the demons they worship.”
Source
1849
A.D.
1774–1849
“Behold Israel, according to the flesh. That is, the people that were the offspring of Israel or Jacob. Are not these they who offered sacrifices to the true God, and eat of the sacrifices, which were offered on his altars, and by offering to him such sacrifices, acknowledged him to be their God, and the only true God: and so you, if you partake, and eat of the sacrifices of idolaters, and of what they tell you was offered to their idols, you seem at least, to join with them in acknowledging, and paying a reverence to their idols, which are devils: and you cannot be partakers of the table of the Lord, and of the table of devils. — Do we provoke the Lord to jealousy? that is, how dare we provoke our Lord, who is a jealous God, and will admit of no rival, by partaking of sacrifices offered to false gods? how dare we thus contemn his power, as if we were stronger than he, or that he could not punish us? (Witham)”
Source
1871
A.D.
1871
“Israel after the flesh--the literal, as distinguished from the spiritual, Israel (Rom 2:29; Rom 4:1; Rom 9:3; Gal 4:29). partakers of the altar--and so of God, whose is the altar; they have fellowship in God and His worship, of which the altar is the symbol.”
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.