Exodus 6:1-6

1 Then the LORD said unto Moses, Now thou shalt see what I will do to Pharaoh; for with a strong hand he must let them go, and with a strong hand he shall drive them out of his land.
2 And God spoke unto Moses and said unto him, I am the LORD;
3 and I appeared unto Abraham, unto Isaac, and unto Jacob, as God Almighty, but by my name the LORD (YHWH) I was not known to them.
4 And I also established my covenant with them, to give them the land of Canaan, the land of their pilgrimage, in which they were strangers.
5 And likewise I have heard the groaning of the sons of Israel, whom the Egyptians keep in bondage, and I have remembered my covenant.
6 Therefore say unto the sons of Israel, I am the LORD, and I will bring you out from under the burdens of the Egyptians, and I will free you out of their bondage, and I will redeem you with a stretched out arm and with great judgments.