Then the Lord said to Moses, "Now you shall see what I will do to Pharaoh: Indeed, by a mighty hand he will let them go; by a mighty hand he will drive them out of his land."
God also spoke to Moses and said to him: "I am the Lord.
I appeared to Abraham, Isaac, and Jacob as God Almighty, but by my name "The Lord' I did not make myself known to them.
References for Exodus 6:3
I also established my covenant with them, to give them the land of Canaan, the land in which they resided as aliens.
I have also heard the groaning of the Israelites whom the Egyptians are holding as slaves, and I have remembered my covenant.
Say therefore to the Israelites, "I am the Lord, and I will free you from the burdens of the Egyptians and deliver you from slavery to them. I will redeem you with an outstretched arm and with mighty acts of judgment.