Memories are often painful. For many people it is simpler and less traumatizing to look toward the unsullied future rather than thinking about what has been in the past.
When Moses addressed the people of Israel on the eve of their entrance into the land of Canaan, he spent a great deal of time reviewing their past history. He also encouraged them to remember that history.
Digging up the decomposing flesh of our past sin, or that of those sins committed against us, is not the motivation behind remembering the past. Listen to how Moses explains God's reasoning.
You may say to yourselves, "These nations are stronger than we are; how can we drive them out?" But do not be afraid of them; remember well what the Lord your God did to Pharaoh and to all Egypt. You saw with your own eyes the great trials, the miraculous signs and wonders, the mighty hand and outstretched arm, with which the Lord your God brought you out. The Lord your God will do the same to all the peoples you now fear" (Deuteronomy 7:17-19).
The task in front of Israel was a huge one. The land they were about to occupy was full of people who would not leave quietly. To occupy the land, Israel had to dislodge the current residents. Forty years earlier ten of twelve spies had reported back to Moses that the land was occupied by giants. Israel needed to remember that giants or not, their God had already proven His ability to do amazing things to provide for, and protect them.
That was the past that they were to remember as they faced an unsullied, but somewhat overwhelming, future.
We don't look back to dig up the sins the Lord has forgiven and buried. We look to the past to remember His faithfulness in bringing us to this point in our lives. We look to what He has done to assure ourselves that He isn't finished "doing" yet.
Israel was to walk with Him with the complete confidence that He would walk with them into the future, and that, with His intervention, the "giants" would shrink to shrimp-size.
We have the advantage of being able to look back at Israel's experience and remember that the God of Israel is our God too. This is especially helpful for those who have not walked with God long enough to have accumulated a lot of experience with His faithfulness. For those of us who have walked with Him for a while, we can look back at our past and remember what He has done in seemingly impossible situations.
I have a small card on which is written: "The future is as bright as the promises of God." To this I would add, "The future is a bright as the faithfulness of God was in the past."
And that is very bright indeed!