Matthew 9:14

Then the disciples of John *came to Him, asking, “Why do we and the Pharisees fast, but Your disciples do not fast?”

Matthew 11:2

Now when John, while imprisoned, heard of the works of Christ, he sent word by his disciples

John 3:25

Therefore there arose a discussion on the part of John’s disciples with a Jew about purification.

John 4:1

Therefore when the Lord knew that the Pharisees had heard that Jesus was making and baptizing more disciples than John

Proverbs 20:6

Many a man proclaims his own loyalty,
But who can find a trustworthy man?

Matthew 6:16

Whenever you fast, do not put on a gloomy face as the hypocrites do, for they neglect their appearance so that they will be noticed by men when they are fasting. Truly I say to you, they have their reward in full.

Matthew 11:18-19

For John came neither eating nor drinking, and they say, ‘He has a demon!’

Mark 2:18-22

John’s disciples and the Pharisees were fasting; and they *came and *said to Him, “Why do John’s disciples and the disciples of the Pharisees fast, but Your disciples do not fast?”

Luke 5:33-39

And they said to Him, “The disciples of John often fast and offer prayers, the disciples of the Pharisees also do the same, but Yours eat and drink.”

Luke 18:9-12

And He also told this parable to some people who trusted in themselves that they were righteous, and viewed others with contempt:

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
Whenever you fast, do not put on a gloomy face as the hypocrites do, for they neglect their appearance so that they will be noticed by men when they are fasting. Truly I say to you, they have their reward in full.
Matthew 11:18
For John came neither eating nor drinking, and they say, ‘He has a demon!’
Proverbs 20:6
Many a man proclaims his own loyalty,
But who can find a trustworthy man?
Mark 2:18
John’s disciples and the Pharisees were fasting; and they *came and *said to Him, “Why do John’s disciples and the disciples of the Pharisees fast, but Your disciples do not fast?”
Luke 5:33
And they said to Him, “The disciples of John often fast and offer prayers, the disciples of the Pharisees also do the same, but Yours eat and drink.”
Luke 18:9
And He also told this parable to some people who trusted in themselves that they were righteous, and viewed others with contempt: