'Fast' in the Bible

“Whenever you fast, don’t be sad-faced like the hypocrites. For they make their faces unattractive so their fasting is obvious to people. I assure you: They’ve got their reward!

But when you fast, put oil on your head, and wash your face,

Then John’s disciples came to Him, saying, “Why do we and the Pharisees fast often, but Your disciples do not fast?”

Jesus said to them, “Can the wedding guests be sad while the groom is with them? The time will come when the groom will be taken away from them, and then they will fast.