The scribes and Pharisees grasp the opportunity to drive a wedge between Jesus’ disciples and the Master. They ask these orthodox Galileans what they think about Jesus’ action: “Why does he eat with tax collectors and sinners?"
Eating where they would not normally eat must have been a troubling thing for the disciples too. Tax collectors and sinners are mentioned in the same breath as people who do not observe the laws of Moses. Because of their job, tax collectors cannot observe the Jewish laws: they execute harsh tax laws, charge interest, do not observe the Sabbath Year, and tolerate a lot of dishonesty. They are people of the world, even though they are Jews. And there are many other Jews whom the scribes and Pharisees treated as sinners because they did not strictly observe the laws.
Eating with these sinners means that you may be given food that is unclean or for which the tithes have not been paid. Respect for the food and drink laws means that you do not eat with those who at the very least raise questions about how they observe the laws of Moses. Now they are trying to bring Jesus’ disciples to their senses by appealing to the law. By eating with all Jews without distinction, does their Master not cause the gains of the reform movement of the Pharisees in Israel to be lost?1
With this question the scribes want to place Jesus in a bad light. If you eat with unclean and sinful people, you will become unclean yourself. You become defiled by those you associate yourself with!
16 And the scribes of the Pharisees, when they saw that he was eating with sinners and tax collectors, said to his disciples, “Why does he eat with tax collectors and sinners?”