Matthew 9:14
"Then came to him the disciples of John, saying, Why do we and the Pharisees fast oft, but thy disciples fast not?"
Cross References (ranked by relevance)
Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward.
Then there arose a question between some of John’s disciples and the Jews about purifying.
When therefore the LORD knew how the Pharisees had heard that Jesus made and baptized more disciples than John,
Most men will proclaim every one his own goodness: but a faithful man who can find?
Now when John had heard in the prison the works of Christ, he sent two of his disciples,