The doctors of the Law brought up the practice of fasting (Luke 5:33). They even named John the Baptist, whom Jesus considered righteous, as siding with them concerning the need to fast. In doing so, they asked Jesus why he and his disciples didn’t fast. Although they named John the Baptist as someone who agreed with them with regard to fasting, they never submitted to John’s call for repentance. Had they done so, they would have received Jesus as their Messiah.
So, what is really behind the scribes’ and Pharisees’ question about fasting, which included using John and his disciples as examples? Jesus had just rebuked the doctors of the Law (Luke 5:32), so they wanted to confront Jesus with an argument that seemed would rebuke him. Jesus had considered John righteous. Why else would he have submitted to be baptized by him (Luke 3:21)? Therefore, the scribes and Pharisees presented Jesus with a paradox of their own (cf. Luke 5:26). If John fasts and is righteous, and they agree with John in this regard, how can Jesus and his disciples be righteous, if they don’t fast?
What they couldn’t see was the totally sterile manner in which they used the fast. Would anyone practice mourning over the death of a loved one, or would one simply enjoy the beloved while the loved one lived? Why schedule a fast twice in the week (cf. Luke 18:10-12)? Who schedules one’s sadness? Once per year God required Israel to mourn over the sins they had committed, which served to separate them from God (and one another). However, what type of mourning could one schedule on a weekly or bi-weekly basis and still maintain the integrity of its purpose (Isaiah 58:3-5)?
Notice how Jesus responded to their question (Luke 5:34). He replied with a picture of a wedding feast. If it would be out of order to mourn (fast) at a wedding, which is a time of supreme joy, why would Jesus’ disciples, who have embraced him as their Messiah, mourn (fast)? Such a thing would be out of order, because the coming of the Messiah was supposed to be a time of fulfillment and great joy.
The doctors of the Law numbered themselves with righteous John who fasted, but what did John do that they did not do (cf. John 3:29-30)? He considered Jesus’ coming as a time for great joy, not mourning (fasting). John embraced Jesus as the Messiah, something the doctors of the Law had been refusing to do up to this point in Luke’s narrative.
Luke shows that Jesus called them on this oversight. The scribes and Pharisees were quick to point out that both they and John and his disciples fasted, but they neglected to mention John’s joy at the coming of the Messiah. Although John 3:29-30 took place about 6 to 7 months later than Jesus’ first confrontation with the Pharisees, the text shows in John 3 that the Pharisees and doctors of the Law knew from the time of Jesus’ baptism that John had endorsed him as the Messiah.
Jesus claimed his disciples would fast after he was taken from them (Luke 5:35), but the sort of fast Jesus’ disciples would be noted for was not merely afflicting one’s soul, but it also involved visiting the widow and the fatherless in their time of need. In other words, Jesus’ disciples would share what they had with the poor who lacked the necessities of life (Isaiah 58:6). The implication was a second rebuke against the scribes and Pharisees who did not share what they had with the needy. While they may have contributed publicly to the treasury (Matthew 6:2; Mark 12:41), they had little regard for the poor to make certain their needs were met. That is, their giving was like their fasting, in that it was meant for others to see and agree that they were righteous. It had nothing to do with their hearts (cf. Joel 2:3).