'Fasting' in the Bible

And when ye fast, be not as the hypocrites, downcast in countenance; for they disfigure their faces, so that they may appear fasting to men: verily I say unto you, They have their reward.

But thou, when fasting, anoint thy head and wash thy face,

so that thou mayest not appear fasting unto men, but to thy Father who is in secret; and thy Father who sees in secret shall render it to thee.

But Jesus, having called his disciples to him, said, I have compassion on the crowd, because they have stayed with me already three days and they have not anything they can eat, and I would not send them away fasting lest they should faint on the way.

But this kind does not go out but by prayer and fasting.