"Those who cannot remember the past are condemned to repeat it. " - George Santayana
Most of us can attest to the truth of this statement. We may understand it from a different perspective like, a mistake is not a waste if we learn from it. Some of the greatest lessons in history and our personal lives were the precursor to some great advances. But how different it could have been if we had failed to learn.
We see this in our relationship with Jesus as well. Nothing is a waste when Yahweh is involved:
And we know that all things work together for good to those who love God, to those who are the called according to purpose. (Romans 8:28)
But what a mess it becomes when we refuse to remember and refuse to learn.
Remember Aaron's mistake (sin) when he made the golden calf and called it the god who had rescued Israel? The nation was almost wiped out on the spot. You would think it would be an historical sin that no one would repeat. Not so. When the kingdom became divided there was concern that people would eventually move to Judah because of the temple. So guess what they did?
Therefore the king asked advice, made two calves of gold, and said to the people, “It is too much for you to go up to Jerusalem. Here are your gods, O Israel, which brought you up from the land of Egypt!” (1 Kings 12:28)
They did what most of us do, they not only repeated their sin but doubled it. "Insanity is doing the same thing over and over again but expecting different results." - Rita Mae Brown. Insanity or not it is what we do with sin when we are not strong in the Lord. Sin seems to cloud our mind but the presence of the Spirit frees it. In the Spirit we are able discern but without him we continue to repeat our sins.
We can't do it on our own and we need to stop trying. We are wasting time, effort and opportunities. If we are really interested in spiritual growth and development we need to embrace the lessons that come from the sins of our past and be willing to be taught in every situation we face. It is part of growing up.