Matthew 9:14

The objections which were made against Christ and his disciples gave occasion to some of the most profitable of his discourses; thus are the interests of truth often served, even by the opposition it meets with from gainsayers, and thus the wisdom of Christ brings good out of evil. This is the third instance of it in this chapter; his discourse of his power to forgive sin, and his readiness to receive sinners, was occasioned by the cavils of the scribes and Pharisees; so here, from a reflection upon the conduct of his family, arose a discourse concerning his tenderness for it. Observe, I. The objection which the disciples of John made against Christ's disciples, for not fasting so often as they did; which they are charged with, as another instance of the looseness of their profession, besides that of eating with publicans and sinners; and it is therefore suggested to them, that they should change that profession for another more strict. It appears by the other evangelists (Mar 2:18 and Luk 5:33) that the disciples of the Pharisees joined with them, and we have reason to suspect that they instigated them, making use of John's disciples as their spokesmen, because they, being more in favour with Christ and his disciples, could do it more plausibly.

— Matthew Henry's Concise Commentary (public domain)