Our Lord Jesus Christ declares this in the Gospel today, where He calls St. Matthew, a prominent tax collector. Later, he throws a party. Many tax collectors attend it. They looked at the tax collectors as public sinners. Jesus was one of the guests. The Pharisees were scandalized by Jesus eating with them. Jesus justifies His associating with them by saying that He was looking for sinners. But those who are not sick, do not need the doctor.