Augustine of Hippo

(De Cons. Ev. ii. 27.) That Matthew writes here mourn, where Mark and Luke write fast, shews that the Lord spake of that kind of fasting which pertains to humbling one’s self in chastisement; as in the following comparisons He may be supposed to have spoken of the other kind which pertains to the joy of a mind wrapt in spiritual thoughts, and therefore averted from the food of the body; shewing that those who are occupied about the body, and owing to this retain their former desires, are not fit for this kind of fasting.