18 John’s disciples and the Pharisees were fasting, and they came and asked him, “Why do John’s disciples and the disciples of the Pharisees fast, but your disciples don’t fast?”

19 Jesus said to them, “Can the groomsmen fast while the bridegroom is with them? As long as they have the bridegroom with them, they can’t fast. 20 But the days will come when the bridegroom will be taken away from them, and then will they fast in that day. 21 No one sews a piece of unshrunk cloth on an old garment, or else the patch shrinks and the new tears away from the old, and a worse hole is made. 22 No one puts new wine into old wineskins, or else the new wine will burst the skins, and the wine pours out, and the skins will be destroyed; but they put new wine into fresh wineskins.”

Mark 2:18-22 - World English Bible

Why fast?

In Mark's gospel, Jesus answered a controversy about spiritual discipline. John's followers and the Pharisees fasted in anticipation of the Messiah. The lack of this popular practice on the part of Jesus' inner circle scandalized both groups.

Jesus answered with three images: the joy of the wedding feast, the repair of a worn cloth and the proper storage of wine in wineskins. In the time of Jesus, the presence of the groom marked the beginning of the wedding feast, a rich Scriptural sign of the Kingdom. The last two images contrasted the old with the new. Old cloth required stretched cloth for proper mending. New wine requires new wineskins to allow for proper fermenting of the wine and expansion of the skins. Notice Jesus used the controversy to highlight himself (bridegroom) and his message (new cloth and new wine). He was unique on the scene; his preaching differed from that of John and the Pharisees. Both groups anticipated the Kingdom; he embodied that reality.

So, if he is who he claims to be, why fast?

We all have certain spiritual practices we cling to. Review yours and seek a good reason to do them. Maybe it's time for a change.