"Let us learn from our Lord's instructions about fasting the great importance of cheerfulness in our religion. Those words, 'put oil on your head and wash your face' (verse 17) are full of deep meaning. They should teach us to aim at letting men see that Christianity makes us happy. Never let us forget that there is no religion in looking melancholy and gloomy. Are we dissatisfied with Christ's wages and Christ's service? Surely not! Then let us not look as if we were."
-J.C. Ryle, Expository Thoughts on Matthew, p. 43-44.