ISB ~ Mark 2 v16

eating with sinners:Table-fellowship was symbolic of personal acceptance and mutual friendship in the ancient Near East. Jesus’ open association with outcasts thus violates the standards of the Pharisees, who regarded sinners and tax collectors as inappropriate company for the religious Jew. They clung to Old Covenant standards of holiness that required Israelites to separate themselves from all sources of uncleanness, including fellowship with Gentiles (Acts 10:28). Jesus exemplifies New Covenant holiness, which extends mercy to everyone in imitation of the Father (Mt 5:43-48; Lk 6:36; CCC 545, 574).

See essay:Who Are the Pharisees?