The reason why the Holy Ghost did not wish the converted Jews to be debarred at once from observing the legal ceremonies, while converted heathens were forbidden to observe the rites of heathendom, was in order to show that there is a difference between these rites. For heathenish ceremonial was rejected as absolutely unlawful, and as prohibited by God for all time; whereas the legal ceremonial ceased as being fulfilled through Christ's Passion, being instituted by God as a figure of Christ.
Reply to Objection 2: According to Jerome, Peter withdrew himself from the Gentiles by pretense, in order to avoid giving scandal to the Jews, of whom he was the Apostle. Hence he did not sin at all in acting thus. On the other hand, Paul in like manner made a pretense of blaming him, in order to avoid scandalizing the Gentiles, whose Apostle he was. But Augustine disapproves of this solution: because in the canonical Scripture (viz. Gal. 2:11 ), wherein we must not hold anything to be false, Paul says that Peter "was to be blamed." Consequently it is true that Peter was at fault: and Paul blamed him in very truth and not with pretense. Peter, however, did not sin, by observing the legal ceremonial for the time being; because this was lawful for him who was a converted Jew. But he did sin by excessive minuteness in the observance of the legal rites lest he should scandalize the Jews, the result being that he gave scandal to the Gentiles.
Reply to Objection 3: Some have held that this prohibition of the apostles is not to be taken literally, but spiritually: namely, that the prohibition of blood signifies the prohibition of murder; the prohibition of things strangled, that of violence and rapine; the prohibition of things offered to idols, that of idolatry; while fornication is forbidden as being evil in itself: which opinion they gathered from certain glosses, which expound these prohibitions in a mystical sense. Since, however, murder and rapine were held to be unlawful even by the Gentiles, there would have been no need to give this special commandment to those who were converted to Christ from heathendom. Hence others maintain that those foods were forbidden literally, not to prevent the observance of legal ceremonies, but in order to prevent gluttony. Thus Jerome says on Ezech. 44:31 ("The priest shall not eat of anything that is dead"): "He condemns those priests who from gluttony did not keep these precepts."
But since certain foods are more delicate than these and more conducive to gluttony, there seems no reason why these should have been forbidden more than the others.
We must therefore follow the third opinion, and hold that these foods were forbidden literally, not with the purpose of enforcing compliance with the legal ceremonies, but in order to further the union of Gentiles and Jews living side by side. Because blood and things strangled were loathsome to the Jews by ancient custom; while the Jews might have suspected the Gentiles of relapse into idolatry if the latter had partaken of things offered to idols. Hence these things were prohibited for the time being, during which the Gentiles and Jews were to become united together. But as time went on, with the lapse of the cause, the effect lapsed also, when the truth of the Gospel teaching was divulged, wherein Our Lord taught that "not that which entereth into the mouth defileth a man" ( Mat. 15:11 ); and that "nothing is to be rejected that is received with thanksgiving" ( 1 Tim. 4:4 ). With regard to fornication a special prohibition was made, because the Gentiles did not hold it to be sinful.