"I am the Lord your God, who brought you out of Egypt, out of the land of slavery."
There is a very real consequence to the existence of God: the existence of the Church. The great "I am" has as its consequence the calling and sanctification of a holy nation from out of slavery.
This is not only an indicative, but an imperative. It is God who calls us to Himself. It is he who makes us holy because he is holy. We exist because God exists and we are called not unto a state of being but unto a way of living (given by the 10 commandments after this Divine proclamation of the name of God and summed up by the Greatest commandment).
We are called to confess "the Lord is our God". We were saved that we might worship him and acknowledge that He is the one who brought us out from the land of slavery to Sin and Death. This is a command to obedience, without which no other commandment bears any weight. We were sanctified unto obedience all because God is. He is the one who has made us. He is the one who has saved us. And He is the one who comforts and perfects us.
It is in the acknowledgement, nay the confession that God is who he is that we worship a thrice holy God. So join with the Church and the Angels through every age and let every knee bow and every tongue confess that Jesus Christ is Lord and Savior, Holy, Holy, Holy is He!