Augustine of Hippo
Catena Aurea · Lukasevangelium 5
And they said unto him, Why do the disciples of John fast often, and make prayers, and likewise the disciples of the Pharisees; but thine eat and drink? And he said unto them, Can ye make the children of the bridechamber fast, while the bridegroom is with them? But the days will come, when the bridegroom shall be taken away from them, and then shall they fast in those days. And he spake also a parable unto them; No man putteth a piece of a new garment upon an old; if otherwise, then both the new maketh a rent, and the piece that was taken out of the new agreeth not with the old. And no man putteth new wine into old bottles; else the new wine will burst the bottles, and be spilled, and the bottles shall perish. But new wine must be put into new bottles; and both are preserved. No man also having drunk old wine straightway desireth new: for he saith, The old is better.
(de Qu. Ev. l. ii. q. 18.) Now there are two fasts, one is in tribulation, to propitiate God for our sins; another in joy, when as carnal things delight us less, we feed the more on things spiritual. The Lord therefore being asked why His disciples did not fast, answered as to each fast. And first of the fast of tribulation; for it follows, And he said unto them, Can ye make the children of the bridegroom fast when the bridegroom is with them?