Exodus 6:2-13 ESV
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. I also established my covenant with them to give them the land of Canaan, the land in which they lived as sojourners. Moreover, I have heard the groaning of the people of Israel whom the Egyptians hold as slaves, and I have remembered my covenant. Say therefore to the people of Israel, ‘I am the LORD, and I will bring you out from under the burdens of the Egyptians, and I will deliver you from slavery to them, and I will redeem you with an outstretched arm and with great acts of judgment. I will take you to be my people, and I will be your God, and you shall know that I am the LORD your God, who has brought you out from under the burdens of the Egyptians. I will bring you into the land that I swore to give to Abraham, to Isaac, and to Jacob. I will give it to you for a possession. I am the LORD.’” Moses spoke thus to the people of Israel, but they did not listen to Moses, because of their broken spirit and harsh slavery.
So the LORD said to Moses, “Go in, tell Pharaoh king of Egypt to let the people of Israel go out of his land.” But Moses said to the LORD, “Behold, the people of Israel have not listened to me. How then shall Pharaoh listen to me, for I am of uncircumcised lips?” But the LORD spoke to Moses and Aaron and gave them a charge about the people of Israel and about Pharaoh king of Egypt: to bring the people of Israel out of the land of Egypt.
ESV: English Standard Version 2016