"Memento chronicles two separate stories of Leonard, an ex-insurance investigator who can no longer build new memories, as he attempts to find the murderer of his wife, which is the last thing he remembers. One story line movies forward in time while the other tells the story backwards revealing more each time." -IMDB
We watched this movie in my Psychology 101 class at UCF and I recall the teacher saying,
"Who would you be, if you didn't know who you were? We are our memories."
That is to say, our identity is equivalent to our memories. As I was talking to Mark a thought emerged about the Old Testament. Often the Jewish people are told, "for I am the Lord your God who brought you out of Egypt."
We are called to remember the greatness of God because our identity as God's people depends upon it!