"61 Still another said, "I will follow you, Lord; but first let me go back and say good-by to my family." 62Jesus replied, "No one who puts his hand to the plow and looks back is fit for service in the kingdom of God." It's from Luke 9. Jesus encounters several people on his walk and they basically all say they will follow Him, and then make excuses and delay the moment of actually taking a step forward. Verses 61 and 62 end the discussion.
He essentially says that if you are doing something for the kingdom of God, you really should not dwell on your past. If you are going to make a commitment, not only are you forgiven and you need to keep on keeping on ;0)
Move forward. Stopping looking back at your past mistakes. Once you start, don't stop.
So, here we go.
Some of us like to have nice lawns. We like to mow beautiful lines into our lawns. Imagine trying to mow that line while looking back. You might be able to do it for a while, but probably after a few times you would see that your lines are no longer straight. Imagine trying to plow and plant in crooked lines. Then try to harvest that!
So stop dwelling on your past mistakes. Embrace the future that God has in store for you. Go in peace and go with God.