Exodus 6:1-3

But the LORD said to Moses, “Now you shall see what I will do to Pharaoh; for with a strong hand he will send them out, and with a strong hand he will drive them out of his land.” God spoke to Moses and said to him, “I am the LORD. I appeared to Abraham, to Isaac, and to Jacob, as God Almighty, but by my name the LORD I did not make myself known to them.