Not as though I had already attained, either were already perfect: but I follow after, if that I may apprehend that for which also I am apprehended of Christ Jesus –Philippians 3:12
I am only intent on “one thing,” says Paul, “in stretching forward to the tings which are before.” But included in this “one thing,” he says, is “forgetting the things which are behind, and stretching forward to the things which are before, I press on toward the goal unto the prize of the high calling of God in Christ Jesus.” Forgetting the past things made him reach forward to the things ahead. So then, any who think they have accomplished it all and need no further perfecting can stop running. They have reached their goal. But those who think they are still far from the goal will never stop running. You should think like the latter, even if you perform ten thousand good deeds. For if Paul thought thus, after ten thousand deaths and so many dangers, how much more should we? … We should act like him, forget our successes, and throw them behind us. For runners don’t think about how many laps they have finished, but how many are left. We, too, should think not about how we are advanced in holiness, but about how much farther we have to go. For how do we profit from what we have when we don’t add what we lack? In addition, Paul didn’t say, “I don’t think about,” but “I don’t even remember.” For we become eager when we diligently work toward what is left, when we forget everything else.
Chrysostom (347-407)
Hudson, Sharrer, Vanker Day by Day with the Early Church Fathers 312