A Question About Fasting

Matthew 9:14) Then the disciples of John came to him, saying, "Why do we and the Pharisees fast, but your disciples do not fast?" 15) And Jesus said to them, "Can the wedding guests mourn as long as the bridegroom is with them? The days will come when the bridegroom is taken away from them, and then they will fast. 16) No one puts a piece of unshrunk cloth on an old garment, for the patch tears away from the garment, and a worse tear is made. 17) Neither is new wine put into old wineskins. If it is, the skins burst and the wine is spilled and the skins are destroyed. But new wine is put into fresh wineskins, and so both are preserved."