Exodus 6:1-3

Then the LORD told Moses, “Now you will see what I will do to Pharaoh. When he feels the force of my strong hand, he will let the people go. In fact, he will force them to leave his land!” And God said to Moses, “I am Yahweh—‘the LORD.’ I appeared to Abraham, to Isaac, and to Jacob as El-Shaddai—‘God Almighty’—but I did not reveal my name, Yahweh, to them.