Matthew 6:16 (KJV)

For if ye forgive men their trespasses, your heavenly Father will also forgive you:

But if ye forgive not men their trespasses, neither will your Father forgive your trespasses.

Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward.

But thou, when thou fastest, anoint thine head, and wash thy face;

That thou appear not unto men to fast, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly.