Genesis 17:7, 19

I will establish My covenant between Me and you and your descendants after you throughout their generations for an everlasting covenant, to be God to you and to your descendants after you. [Gal 3:16]

But God said, “No, Sarah your wife shall bear you a son indeed, and you shall name him Isaac (laughter); and I will establish My covenant with him for an everlasting covenant and with his descendants after him.