As we get older, we have a tendency to look back, and if we aren’t careful, to give in to the selective eyesight that sees only the problems and failures of the past. It's too easy to look for someone in the past to blame or resent and way too easy to stumble around in bitterness and regret.
The best thing to do with the past is to learn from it, while keeping our eyes on today and looking forward to the days to come!
Jesus talks about a man who "looks back" because he is not ready for service in the kingdom of God (Luke 9:62). Now what that passage is telling us is that the past can be a distraction that keeps us from being what the Lord needs us to be today!
The apostle Paul talks about "Forgetting what is behind and straining toward what is ahead. I press on toward the goal..." (Philippians 3:13). We've got to stay centered in today, seeking to honor God and living for his future for us.
The best way to change the past is to leave the past and live the Kingdom! We seek to live the way God wants us to live today, rooted in the moment and living for God and his future, living in service to others and God's Kingdom.