In this passage, we see the beginning of the expression - I am: the phrase God uses to name himself. We get a sense of both His transcendence and imminence as we see God Almighty and a very personal God. When Moses asks God who He is he replies 'I Am' which is a verb meaning to be. Essentially, God is telling Moses and us - I am who I am, I have been who I have been and I will be who I will be. He is self existent. And this is simply unfathomable. In the same way - who is Jesus? I am. In the same way Moses could depend upon the work and promises of I am, we can depend upon Jesus. He will be our God and we will be his people.