'Fasting' in the Bible

"Moreover when you fast, don't be like the hypocrites, with sad faces. For they disfigure their faces, that they may be seen by men to be fasting. Most certainly I tell you, they have received their reward.

so that you are not seen by men to be fasting, but by your Father who is in secret, and your Father, who sees in secret, will reward you.

Jesus summoned his disciples and said, "I have compassion on the multitude, because they continue with me now three days and have nothing to eat. I don't want to send them away fasting, or they might faint on the way."

But this kind doesn't go out except by prayer and fasting."