Matthew 6:16-18

¹⁶Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may be seen of men to fast. Verily I say unto you, They have received their reward. ¹⁷But thou, when thou fastest, anoint thy head, and wash thy face; ¹⁸that thou be not seen of men to fast, but of thy Father who is in secret: and thy Father who seeth in secret shall recompense thee.