Can the children of the bridechamber mourn, as long as the bridegroom is with them? — Matt 9:15
Christianity is a religion of sincerity, and not empty forms. The Jews had drifted away from spiritual religion, and in consequence had multiplied meaningless ceremonies. They may have been in the midst of joy and gladness, but when the prescribed hour for fasting came they out on their sackcloth and other marks of sorrow, began to wear sad looks, and entered upon the set period of mourning. Such a practice led to insincerity. Ofttimes it was an utterly false expression of the inner life.
Jesus struck a blow at this hollowness, and refused to conform to it. Fasting is a symbol of mourning, of sorrow; to go through the form of fasting, therefore, when the heart is joyous, is only a farce. When there is an occasion for mourning, let there be a mourning, but not otherwise. That is, Jesus teaches that our religion must always be sincere, never affected or hypocritical. He condemns as sacrilegious all over expressions of religious emotion or feeling.