Matthew 6:16-18
Fasting
16“aNow whenever you fast, do not put on a gloomy face as the hypocrites do, for they 1neglect their appearance so that they will be noticed by men when they are fasting. bTruly I say to you, they have their reward in full. 17“But you, when you fast, aanoint your head and wash your face 18so that your fasting will not be noticed by men, but by your Father who is in secret; and your aFather who sees what is done in secret will reward you.