The Pharisees and scribes are judging Jesus and his disciples by purely external acts, in this case, fasting. Jesus' reply basically says that there is nothing wrong with fasting and it can be a very good thing but the way of life that he is urging us to follow is based on a completely different foundation, our inner relationship with God and with those around us, a relationship based on love and caring for others. If that is not there, even the most severe fasting has little value. The old cloth, the old wineskins of the Pharisees (and people who think like them) cannot contain the new thinking of Jesus and has to be abandoned. We, too, cannot measure our Catholic life and that of others by purely external observances but it is the inner spirit of love for those around us in our daily life which is the real measure of our closeness to God.