Genesis 15-17 (ESV)
God’s Covenant with Abram
15:1 After these things the word of the Lord came to Abram in a vision: “Fear not, Abram, I am your shield; your reward shall be very great.” 2 But Abram said, “O Lord God, what will you give me, for I continue  childless, and the heir of my house is Eliezer of Damascus?”3 And Abram said, “Behold, you have given me no offspring, and a member of my household will be my heir.” 4 And behold, the word of theLord came to him: “This man shall not be your heir; your very own son  shall be your heir.” 5 And he brought him outside and said, “Look toward heaven, and number the stars, if you are able to number them.” Then he said to him, “So shall your offspring be.” 6 And he believed theLord, and he counted it to him as righteousness.
7 And he said to him, “I am the Lord who brought you out from Ur of the Chaldeans to give you this land to possess.” 8 But he said, “O LordGod, how am I to know that I shall possess it?” 9 He said to him, “Bring me a heifer three years old, a female goat three years old, a ram three years old, a turtledove, and a young pigeon.” 10 And he brought him all these, cut them in half, and laid each half over against the other. But he did not cut the birds in half. 11 And when birds of prey came down on the carcasses, Abram drove them away.
12 As the sun was going down, a deep sleep fell on Abram. And behold, dreadful and great darkness fell upon him. 13 Then the Lord said to Abram, “Know for certain that your offspring will be sojourners in a land that is not theirs and will be servants there, and they will be afflicted for four hundred years. 14 But I will bring judgment on the nation that they serve, and afterward they shall come out with great possessions.15 As for yourself, you shall go to your fathers in peace; you shall be buried in a good old age. 16 And they shall come back here in the fourth generation, for the iniquity of the Amorites is not yet complete.”
17 When the sun had gone down and it was dark, behold, a smoking fire pot and a flaming torch passed between these pieces. 18 On that day the Lord made a covenant with Abram, saying, “To your offspring I give  this land, from the river of Egypt to the great river, the river Euphrates, 19 the land of the Kenites, the Kenizzites, the Kadmonites, 20 the Hittites, the Perizzites, the Rephaim, 21 the Amorites, the Canaanites, the Girgashites and the Jebusites.”
Sarai and Hagar
16:1 Now Sarai, Abram’s wife, had borne him no children. She had a female Egyptian servant whose name was Hagar. 2 And Sarai said to Abram, “Behold now, the Lord has prevented me from bearing children. Go in to my servant; it may be that I shall obtain children  by her.” And Abram listened to the voice of Sarai. 3 So, after Abram had lived ten years in the land of Canaan, Sarai, Abram’s wife, took Hagar the Egyptian, her servant, and gave her to Abram her husband as a wife. 4 And he went in to Hagar, and she conceived. And when she saw that she had conceived, she looked with contempt on her mistress.  5 And Sarai said to Abram, “May the wrong done to me be on you! I gave my servant to your embrace, and when she saw that she had conceived, she looked on me with contempt. May the Lord judge between you and me!”6 But Abram said to Sarai, “Behold, your servant is in your power; do to her as you please.” Then Sarai dealt harshly with her, and she fled from her.
7 The angel of the Lord found her by a spring of water in the wilderness, the spring on the way to Shur. 8 And he said, “Hagar, servant of Sarai, where have you come from and where are you going?” She said, “I am fleeing from my mistress Sarai.” 9 The angel of the Lord said to her, “Return to your mistress and submit to her.” 10 The angel of the Lord also said to her, “I will surely multiply your offspring so that they cannot be numbered for multitude.” 11 And the angel of the Lord said to her,
“Behold, you are pregnant
and shall bear a son.
You shall call his name Ishmael, 
because the Lord has listened to your affliction.
12 He shall be a wild donkey of a man,
his hand against everyone
and everyone’s hand against him,
and he shall dwell over against all his kinsmen.”
13 So she called the name of the Lord who spoke to her, “You are a God of seeing,”  for she said, “Truly here I have seen him who looks after me.”  14 Therefore the well was called Beer-lahai-roi;  it lies between Kadesh and Bered.
15 And Hagar bore Abram a son, and Abram called the name of his son, whom Hagar bore, Ishmael. 16 Abram was eighty-six years old when Hagar bore Ishmael to Abram.
Abraham and the Covenant of Circumcision
17:1 When Abram was ninety-nine years old the Lord appeared to Abram and said to him, “I am God Almighty;  walk before me, and be blameless, 2 that I may make my covenant between me and you, and may multiply you greatly.” 3 Then Abram fell on his face. And God said to him, 4 “Behold, my covenant is with you, and you shall be the father of a multitude of nations. 5 No longer shall your name be called Abram,  but your name shall be Abraham,  for I have made you the father of a multitude of nations. 6 I will make you exceedingly fruitful, and I will make you into nations, and kings shall come from you. 7 And I will establish my covenant between me and you and your offspring after you throughout their generations for an everlasting covenant, to be God to you and to your offspring after you. 8 And I will give to you and to your offspring after you the land of your sojournings, all the land of Canaan, for an everlasting possession, and I will be their God.”
9 And God said to Abraham, “As for you, you shall keep my covenant, you and your offspring after you throughout their generations.10 This is my covenant, which you shall keep, between me and you and your offspring after you: Every male among you shall be circumcised.11 You shall be circumcised in the flesh of your foreskins, and it shall be a sign of the covenant between me and you. 12 He who is eight days old among you shall be circumcised. Every male throughout your generations, whether born in your house or bought with your money from any foreigner who is not of your offspring, 13 both he who is born in your house and he who is bought with your money, shall surely be circumcised. So shall my covenant be in your flesh an everlasting covenant. 14 Any uncircumcised male who is not circumcised in the flesh of his foreskin shall be cut off from his people; he has broken my covenant.”
Isaac’s Birth Promised
15 And God said to Abraham, “As for Sarai your wife, you shall not call her name Sarai, but Sarah  shall be her name. 16 I will bless her, and moreover, I will give  you a son by her. I will bless her, and she shall become nations; kings of peoples shall come from her.”17 Then Abraham fell on his face and laughed and said to himself, “Shall a child be born to a man who is a hundred years old? Shall Sarah, who is ninety years old, bear a child?” 18 And Abraham said to God, “Oh that Ishmael might live before you!” 19 God said, “No, but Sarah your wife shall bear you a son, and you shall call his name Isaac.  I will establish my covenant with him as an everlasting covenant for his offspring after him. 20 As for Ishmael, I have heard you; behold, I have blessed him and will make him fruitful and multiply him greatly. He shall father twelve princes, and I will make him into a great nation. 21 But I will establish my covenant with Isaac, whom Sarah shall bear to you at this time next year.”
22 When he had finished talking with him, God went up from Abraham. 23 Then Abraham took Ishmael his son and all those born in his house or bought with his money, every male among the men of Abraham’s house, and he circumcised the flesh of their foreskins that very day, as God had said to him. 24 Abraham was ninety-nine years old when he was circumcised in the flesh of his foreskin. 25 And Ishmael his son was thirteen years old when he was circumcised in the flesh of his foreskin. 26 That very day Abraham and his son Ishmael were circumcised. 27 And all the men of his house, those born in the house and those bought with money from a foreigner, were circumcised with him.