Neither do men put new wine into old wineskins: else the wineskins break, and the wine runs out, and the wineskins perish: but they put new wine into new wineskins, and both are preserved.
All Commentaries on Matthew 9:17 Go To Matthew 9
Jerome
AD 420
O boastful enquiry and ostentation of fasting much to be blamed, nor can John's disciples be excused for their taking part with the Pharisees who they knew had been condemned by John, and for bringing a false accusation against Him whom they knew their master had preached.
Christ is the Bridegroom and the Church the Bride. Of this spiritual union the Apostles were born; they cannot mourn so long as they see the Bridegroom in the chamber with the Bride. But when the nuptials are past, and the time of passion and resurrection is come, then shall the children of the Bridegroom fast. "The days shall come when the bridegroom shall be taken from them, and then shall they fast.”.
Hence some think that a fast ought to follow the forty days of Passion, although the day of Pentecost and the coming of the Holy Spirit immediately bring back our joy and festival. From this text accordingly, Montanus, Prisca, and Maximilla enjoin a forty days abstinence after Pentecost, but it is the use of the Church to come to the Lord’s passion and resurrection through humiliation of the flesh, that by carnal abstinence we may better be prepared for spiritual fulness.
Otherwise; By the “old garment,” and “old skins,” we must understand the Scribes and Pharisees; and by the “piece of new cloth,” and “new wine,” the Gospel precepts, which the Jews were not able to bear; so “the rent was made worse.” Something such the Galatians sought to do, to mix the precepts of the Law with the Gospel, and to put new wine into old skins. The word of the Gospelis therefore to be poured into the Apostles, rather than into the Scribes and Pharisees, who, corrupted by the traditions of the elders, were unable top reserve the purity of Christ’s precepts.
Or, when He has departed from us for our sins, then is a fast to be proclaimed, then is mourning to be put on.