The response of Jesus is clearly metaphorical, yet strangely rude. Ancient Hebrew marriage customs are being indicated here, and Jesus places himself in the context of being the “bridegroom” at his moment of consummation.
Ancient Hebrew marriages were highly ritualized contract negotiations between two families. In the earliest days, men would pay a dowry to marry off their sons. At the rite of betrothal, money would change hands and contracts were signed between the men of the two respective houses. Sometime later, a wedding rite would occur when the couple would couple, either at the bride’s house, or back at the groom’s house, in front of everyone, or at least a handful of attendants, all watching for the fateful moment of insemination. This event is celebrated, sometimes over several days, with feasting and drink.
The Pharisee scribes come to Jesus with a complaint about the time: it’s time to fast now, according to their traditions. They can impose their authority on the followers of John the Baptist, and now they come to impose it upon Jesus and his house. Jesus replies in a way that points out his authority would always trump theirs.
Jesus is eating and drinking with Romans and other non-Jewish people, then he describes this as a “wedding feast” and himself as the “bridegroom”. In such a context, the Romans would be the family of the groom, and the Judeans the family of the bride, as here he was conjoining the families of Rome and Judea together as if in a wedding. That at some point in the recent past there was a betrothal, and now the wedding day has come.