Matthew 9:14

Then John's disciples went up to Him, and said, "Why do we and the Pharisees practice fasting, but your disciples do not?"

Matthew 11:2

Now when John in prison heard of the doings of the Christ, he sent this message by his disciples:

John 3:25

Then a discussion came up between John's disciples and a Jew about purification.

John 4:1

Now when the Lord learned that the Pharisees had heard that He was winning and baptizing more disciples than John --

Matthew 6:16

"Also whenever you fast, you must not look gloomy like the hypocrites, for they put on a gloomy countenance, to let people see them fasting. I solemnly say to you, they already have their reward.

Matthew 11:18-19

For John came neither eating nor drinking with others, and yet they said, 'He has a demon.'

Mark 2:18-22

Now John's disciples and the Pharisees were keeping a fast. So some people came and asked Him, "Why do John's disciples and the Pharisees' disciples practice fasting, but yours never do?"

Luke 5:33-39

After that they said to Him, "John's disciples rigidly practice fasting and offering up prayers; so do the Pharisees, but your disciples keep right on eating and drinking."

Luke 18:9-12

To some people who were confident that they themselves were upright, but who scorned everybody else, He told the following story:

Treasury of Scripture Knowledge

Summary

Then came to him the disciples of John, saying, Why do we and the Pharisees fast oft, but thy disciples fast not?

Bible References

Why

Matthew 6:16
"Also whenever you fast, you must not look gloomy like the hypocrites, for they put on a gloomy countenance, to let people see them fasting. I solemnly say to you, they already have their reward.
Matthew 11:18
For John came neither eating nor drinking with others, and yet they said, 'He has a demon.'
Mark 2:18
Now John's disciples and the Pharisees were keeping a fast. So some people came and asked Him, "Why do John's disciples and the Pharisees' disciples practice fasting, but yours never do?"
Luke 5:33
After that they said to Him, "John's disciples rigidly practice fasting and offering up prayers; so do the Pharisees, but your disciples keep right on eating and drinking."
Luke 18:9
To some people who were confident that they themselves were upright, but who scorned everybody else, He told the following story: