Expositor's Bible Commentary Commentary Mark 2:20

"But the days will come, when the bridegroom shall be taken away from them, and then will they fast in that day." — Mark 2:20 (ASV)

Jesus answers in a parable emphasizing the joy that the presence of Jesus makes possible. Therefore fasting, as a sign of mourning, is not appropriate. To fast during a wedding, a time of great joy and festivity, would be unthinkable. Jesus is the bridegroom (v.19) and his disciples the guests. While he remains with them they will rejoice, not fast. However, he will not always be with them. When he is taken away, fasting will be appropriate. This is probably a veiled reference to his death (the word used implies a violent removal that causes sorrow).