At the beginning of today’s Gospel reading, we see some disciples of St. John the Baptist asking Jesus why His disciples did not fast as they and the Pharisees did. There are two interesting things to note about this. The first is that the disciples of St. John were comparing themselves to the Pharisees in terms of fasting; both groups “fast much,” they said, while Jesus’ disciples did not fast at all. The second is that these men were still disciples of John the Baptist, despite his repeatedly saying that he was not the One Whom they should be following.
God sent John the Baptist to prepare the way for the coming of His Son; as soon as the time had come for Jesus to begin His public ministry, St. John publicly declared Him to be the Lamb of God Whom his disciples should now follow (cf. Jn 1:29-30 DRB). The disciples who approached Jesus in today’s Gospel had not heeded St. John’s instruction to follow Christ. Their words reveal that they continued to steadfastly cling to the ways of the Old Law like the Pharisees.
In His reply, Jesus showed how He had come to fulfill the Old Law but not to abolish it. He said that the days will come when His disciples would fast, but it was not right for them to do so yet, because He was still with them. They would fast during the undetermined number of millennia between His Ascension and His Second Coming, preparing to meet Him again.
He gave the reason for this in the next part of His answer: “People do not put new wine into old wineskins. Otherwise the skins burst, the wine spills out, and the skins are ruined.”
Those who choose to cling to their old ways of sin are like the old wineskins. They are too attached to their bad habits and vices to accept the teachings of Jesus; rather than being able to retain His Word and the graces that come with it, their souls metaphorically burst, and the graces are lost. On our own, we cannot change; this can only happen through the work of grace in our souls. However, we in turn must be open to accepting this grace and allow it to change our hearts.
God has given us free will; He never forces Himself into our hearts. Through fasting and other penances, we work to overcome our wills, which have become inclined toward sin as a result of Original Sin. Both prayer and penance are necessary to soften our hearts so that we might be like new wineskins, eager and ready to receive and retain the Word of God and the graces He offers us.