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. Lay not up for yourselves treasures upon earth, where moth and rust doth corrupt, and where thieves break through and steal:
But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal: For where your treasure is, there will your heart be also. The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.
Read More Here: What Does The Bible Say About Fasting?