Read through the scriptures with one word in mind, and you will start to see it everywhere. Remember. Remember the Lord thy God. Remember how merciful he has been. Remember the words. Remember the covenant. Alongside it runs its shadow, the warning to forget not. Few commands are repeated as often, across as many books and centuries, as the command to remember. It is worth asking why God says it so much, and what modern science has learned about memory that might help us hear the command freshly.