Ambrose of Milan — as excerpted in the Catena Aurea on Luke 5:33-39

“Lastly, it is spoken of the fast of the soul, as the context shews, for it follows, But he said, No man putteth a piece of a new garment upon an old. He calleth fasting an old garment, which the Apostle thought should be taken off, saying, Put off the old man with his deeds. (Col. 3:9.) In the same manner we have a series of precepts not to mix up the actions of the old and new man.”