Thematic Bible: How not to fast

"In addition, when you fast [i.e., go without food and/or drink for religious reasons], do not be like the hypocrites with long faces, for they go around with gloomy expressions on their faces in order to advertise that they are fasting. It is true when I say to you, these people have [already] received their reward. But when you fast, groom your hair and wash your face so that people will not see that you are fasting, but [only] your Father who is in secret [will know about it]. For, [since] He sees [what is done] in secret, He will repay you.