Philip. 3:12-16 (ESV)
Not that I have already obtained this or am already perfect, but I press on to make it my own, because Christ Jesus has made me his own.  Brothers, I do not consider that I have made it my own. But one thing I do: forgetting what lies behind and straining forward to what lies ahead,  I press on toward the goal for the prize of the upward call of God in Christ Jesus.  Let those of us who are mature think this way, and if in anything you think otherwise, God will reveal that also to you.  Only let us hold true to what we have attained.
Forgetting what lies behind and straining forward to what lies ahead. A man running a race can’t afford to look behind, otherwise those behind overtake him. If he wants his best run he can only look forward. The Christian runs a race, and at the finish line is the Cross. It is our future, it is our salvation. We dare not take our eyes off it. We strain forward toward it. The past is full of sin. Always sin. We look in the past and see our sin and despair. We look in the past and see our sin disguised as good works building up our pride, and we sin. The past has nothing for us. Oh we can learn from it. Don’t get me wrong. But it is not good to dwell on it. Dwelling on it is dangerous, learn from it, but move on look to the cross. Only in the cross is the past and present forgiven. Because in the cross, Christ makes us his own.