G-d sets an everlasting covenant with Abram and his descendants

• Abram was 99 years old, and G-d appeared to Abram, and He said to him, "I am the Almighty God; walk before Me and be perfect. And I will place My covenant between Me and between you, and I will multiply you very greatly."
  
  
• And Abram fell upon his face, and G-d spoke with him, saying, "As for Me, behold My covenant is with you, and you shall become the father of a multitude of nations. And your name shall no longer be called Abram, but your name shall be Abraham, for I have made you the father of a multitude of nations. And I will make you exceedingly fruitful, and I will make you into nations, and kings will emerge from you. And I will establish My covenant between Me and between you and between your seed after you throughout their generations as an everlasting covenant, to be to you for a God and to your seed after you. And I will give you and your seed after you the land of your sojournings, the entire land of Canaan for an everlasting possession, and I will be to them for a God."
  
  
• And G-d said to Abraham, "And you shall keep My covenant, you and your seed after you throughout their generations. This is My covenant, which you shall observe between Me and between you and between your seed after you, that every male among you be circumcised. And you shall circumcise the flesh of your foreskin, and it shall be as the sign of a covenant between Me and between you. And at the age of eight days, every male shall be circumcised to you throughout your generations, one that is born in the house, or one that is purchased with money, from any foreigner, who is not of your seed. Those born in the house and those purchased for money shall be circumcised, and My covenant shall be in your flesh as an everlasting covenant. And an uncircumcised male, who will not circumcise the flesh of his foreskin-that soul will be cut off from its people; he has broken My covenant."
  
  
• And G-d said to Abraham, "Your wife Sarai-you shall not call her name Sarai, for Sarah is her name. And I will bless her, and I will give you a son from her, and I will bless her, and she will become [a mother of]nations; kings of nations will be from her. "
  
  
• And Abraham fell on his face and rejoiced, and he said to himself, "Will[a child]be born to one who is a hundred years old, and will Sarah, who is ninety years old, give birth?" And Abraham said to G-d, "If only Ishmael will live before You!"
  
  
• And G-d said, "Indeed, your wife Sarah will bear you a son, and you shall name him Isaac, and I will establish My covenant with him as an everlasting covenant for his seed after him. And regarding Ishmael, I have heard you; behold I have blessed him, and I will make him fruitful, and I will multiply him exceedingly; he will beget twelve princes, and I will make him into a great nation. But My covenant I will establish with Isaac, whom Sarah will bear to you at this time next year." And He finished speaking with him, and G-d went up from above Abraham.
  
  
• Abraham circumcised all males in the household, on that very day, as G-d had spoken with him. Ishmael was 13 years old at the time.

• I am the Almighty G-d Heb. שַׁדַי -I am He Whose G-dliness suffices for every creature. [שֶׁ that, דַי is sufficient]. Wherever it (this name) appears in Scripture, it means “His sufficiency,” but each one is to be interpreted according to the context. [Gen. Rabbah 47:3]
• walk before Me and be perfect Serve me with faith and honesty, and also be perfect in all My trials.
• Abraham - אברהם In Hebrew, father is אב
• you shall not call her name Sarai which means “my princess,” for me, but not for others. But Sarah, in an unqualified sense, shall be her name, that she will be a princess over all. — [from Ber. 13a]
• If only Ishmael will live that would be enough, I do not deserve to receive such a reward as this.
• and you shall name him Isaac Heb. יִצְחָק, because of the rejoicing (צְחוֹק)