Mattithyahu (Matthew) 6:16-18

“And when you fast, do not be sad-faced like the hypocrites. For they disfigure their faces so that they appear to be fasting to men. Truly, I say to you, they have their reward. But you, when you fast, anoint your head and wash your face, so that you do not appear to men to be fasting, but to your Father who is in the secret place. And your Father who sees in secret shall reward you openly.