Tax collectors were among the most notorious cheaters in the political circles of Jesus time. Jesus compared them to someone who refuses to listen to God (Mt 18:17). They were despised people that no one trusted. Yet Jesus called one of them to be his disciple, Mathew, the author of the book we are studying (Mt 9:9).
Jesus himself had a mixed reputation. He was called a prophet (John 6:14), a teacher (John 3:2), a drunk (Lk 7:33), a glutton (Mt 11:19), the Christ (John 7:31), and a friend of tax collectors (Mt 11:19). He hung around people of low reputation (Mathew 9:10) knowing exactly who they were (John 2:25). This shows us when we look on outward appearances we can be dead wrong.
But Jesus looked in the heart for faith in God (Jn 7:24, 8:15). People were changed by their encounter with the Savior (Lk 19:8). Our past does not need to haunt us (1 Corinthians 6:11). Jesus has changed who we were into whom he designed us to be (2 Corinthians 5:17).