'Fasting' 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!

so that you don’t show your fasting to people but to your Father who is in secret. And your Father who sees in secret will reward you.

[However, this kind does not come out except by prayer and fasting.]”