Parashat Va’era
God made His Name known to Moses and the children of Israel in a way that Abraham, Isaac and Jacob had not known Him. They knew Him as El Shaddai, the All Sufficient One, but now He was going to make Himself known by His Name, YHVH.
I am HASHEM, and I will bring you out from under the burdens of the Egyptians. I will deliver you from their bondage, and I will redeem you with an outstretched arm and with great judgments. I will take you to Myself as a people, and I will be your God. You will know that I am HASHEM your God, who brought you out from under the burdens of the Egyptians.
exodus 6:6-7