Brethren, I count not myself to have apprehended: but this one thing I do, forgetting those things which are behind, and reaching forth unto those things which are before,  I press toward the mark for the prize of the high calling of God in Christ Jesus.
What must we do to serve God better? We need to forget those things behind us. We cannot keep worrying about yesterday. Yesterday is done never to be seen again. We cannot change our past, but we can learn from it. Forget about your past mistakes. Ask forgiveness from God and forget it. Then reach forth to tomorrow. Press toward (not behind) the mark for the prize.
The winner of a race never wins by looking back, but by keeping his eyes on the finish line. Keep your eyes toward Jesus. When you look back, or dwell on your past, your eyes are no longer on the Lord.
Motto for today: Look forward, not back.
Have a great day.