Matthew 6:16-18

¶ 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 already have their reward. But thou, when thou dost fast, anoint thine head, and wash thy face that thou appear not unto men to fast, but unto thy Father who is in secret; and thy Father, who sees in secret, shall reward thee openly.