16 The Apostle does indeed blame those who forbade marriage, and commanded to abstain from food, which God created for use with thanksgiving. But he has in view Marcion, and Tatian, and other heretics, who inculcate perpetual abstinence, to destroy, and express their hatred and contempt for, the works of the Creator. But we praise every creature of God, and yet prefer leanness to corpulence, abstinence to luxury, fasting to fullness. “He that labours labours for himself, and he is eager to his own destruction.”
And, “From the days of John the Baptist (who fasted and was a virgin) until now the kingdom of heaven suffers violence, and men of violence take it by force.” For we are afraid lest at the coming of the eternal judge we be caught, as in the days of the flood, and at the overthrow of Sodom and Gomorrha, eating and drinking, and marrying, and giving in marriage. For both the flood and the fire from heaven found fullness as well as marriage ready for destruction. Nor need we wonder if the Apostle commands that everything sold in the market be bought and eaten, since with idolaters, and with those who still ate in the temples of the idols meats offered to idols as such, it passed for the highest abstinence to abstain only from food eaten by the Gentiles.
And if he says to the Romans: “Let not him that eats set at nought him that eats not: and let not him that eats not judge him that eats,” he does not make fasting and fullness of equal merit, but he is speaking against those believers in Christ who were still judaizing: and he warns Gentile believers, not to offend those by their food who were still too weak in faith. In brief this is clear enough in the sequel: “I know and am persuaded in the Lord Jesus, that nothing is unclean of itself: save that to him who accounts anything to be unclean, to him it is unclean.
For if because of meat your brother is grieved, you walk no longer in love. Destroy not with your meat him for whom Christ died. Let not then your good be evil spoken of: for the Kingdom of God is not eating and drinking.” And that no one may suppose he is referring to fasting and not to Jewish superstition, he immediately explains, “One man has faith to eat all things: but he that is weak eats herbs.” And again, “One man esteems one day above another: another esteems every day alike.
Let each man be fully assured in his own mind. He that regards the day, regards it unto the Lord: and he that eats, eats unto the Lord, for he gives God thanks; and he that eats not, unto the Lord he eats not, and gives God thanks.” For they who were still weak in faith and thought some meats clean, some unclean: and supposed there was a difference between one day and another, for example, that the Sabbath, and the New Moons, and the Feast of Tabernacles were holier than other days, were commanded to eat herbs which are indifferently partaken of by all. But such as were of stronger faith believed all meats and all days to be alike.
Source: Against Jovinianus (New Advent)