In Christ's Own Words:

As Jesus passed there, he saw a man named Matthew sitting at the customs post. He said to him, "Follow me." And he got up and followed him. While he was at table in his house, many tax collectors and sinners came and sat with Jesus and his disciples. The Pharisees saw this and said to his disciples, "Why does your teacher eat with tax collectors and sinner?" He heard this and said, "Those who are well do not need a physician, but the sick do."
Matthew 9:9-12