Historical Context: This portion of our history, takes place at approximately 3'000 B.C.
Authorship: The Torah books are all attributed to the authorship of Moses, which he most probably wrote during Israel's forty-year period of wandering in the desert. Some editorial remarks were later added to these books by priests and other divinely inspired writers, such as Joshua and Samuel.
1 When Abram was ninety-nine years old, the LORD appeared to him and said, "I am God Almighty ; walk before me and be blameless.
What does God command Abram to do? To walk before Him and be blameless. To be in a relationship with God and not to sin.
2 I will confirm my covenant between me and you and will greatly increase your numbers."
Why does God need to confirm the covenant? Because it's been about fourteen years since God had appeared to Abram. Abram thought that he had solved the problem by having Ishmael with Hagar, but now God needs to remind him that that was not the deal. That was not the plan that God had in mind.
3 Abram fell facedown, and God said to him,
Why does Abram fall facedown? Because God appeared to him. Any time God talks to us or does something for us, the appropriate response is to worship Him, which is what Abram is doing.
4 "As for me, this is my covenant with you: You will be the father of many nations. 5 No longer will you be called Abram ; your name will be Abraham, for I have made you a father of many nations. 6 I will make you very fruitful; I will make nations of you, and kings will come from you.
Did any kings ever come out of Abraham's descendants? All the Kings of Israel. Abraham had Isaac. Isaac had Jacob. Jacob's descendants became the kings. Saul, David, Solomon, etc.
7 I will establish my covenant as an everlasting covenant between me and you and your descendants after you for the generations to come, to be your God and the God of your descendants after you. 8 The whole land of Canaan, where you are now an alien, I will give as an everlasting possession to you and your descendants after you; and I will be their God."
9 Then God said to Abraham, "As for you, you must keep my covenant, you and your descendants after you for the generations to come. 10 This is my covenant with you and your descendants after you, the covenant you are to keep: Every male among you shall be circumcised. 11 You are to undergo circumcision, and it will be the sign of the covenant between me and you. 12 For the generations to come every male among you who is eight days old must be circumcised, including those born in your household or bought with money from a foreigner—those who are not your offspring. 13 Whether born in your household or bought with your money, they must be circumcised. My covenant in your flesh is to be an everlasting covenant. 14 Any uncircumcised male, who has not been circumcised in the flesh, will be cut off from his people; he has broken my covenant."
What is Abram's part of the covenant? To be circumcised. That was the sign that Abraham and his descendants were in a covenant, in a relationship, with God. Do we have to be circumcised now to be in covenant or in relationship with God?
Romans 2:28-29 - A man is not a Jew if he is only one outwardly, nor is circumcision merely outward and physical. 29No, a man is a Jew if he is one inwardly; and circumcision is circumcision of the heart, by the Spirit, not by the written code. Such a man's praise is not from men, but from God.
This is telling us that the sign of the covenant is not really whether you're circumcised or not. You're relationship with God does not depend on a physical marking. It depends on whether or not God's Spirit has changed our heart. Physical circumcision is changing the outward appearance of your body. Spiritual circumcision is changing your heart.
15 God also said to Abraham, "As for Sarai your wife, you are no longer to call her Sarai; her name will be Sarah. 16 I will bless her and will surely give you a son by her. I will bless her so that she will be the mother of nations; kings of peoples will come from her."
17 Abraham fell facedown; he laughed and said to himself, "Will a son be born to a man a hundred years old? Will Sarah bear a child at the age of ninety?" 18 And Abraham said to God, "If only Ishmael might live under your blessing!"
Why is Abraham laughing? He thinks that it's impossible for a man and a woman as old as Abraham and Sarah are to have children. Is anything impossible for God? Of course not. God is about to do a miracle for Abraham and Sarah, but that's still hard for Abraham to believe.
19 Then God said, "Yes, but your wife Sarah will bear you a son, and you will call him Isaac. I will establish my covenant with him as an everlasting covenant for his descendants after him. 20 And as for Ishmael, I have heard you: I will surely bless him; I will make him fruitful and will greatly increase his numbers. He will be the father of twelve rulers, and I will make him into a great nation. 21 But my covenant I will establish with Isaac, whom Sarah will bear to you by this time next year." 22 When he had finished speaking with Abraham, God went up from him.
23 On that very day Abraham took his son Ishmael and all those born in his household or bought with his money, every male in his household, and circumcised them, as God told him. 24 Abraham was ninety-nine years old when he was circumcised, 25 and his son Ishmael was thirteen; 26 Abraham and his son Ishmael were both circumcised on that same day. 27 And every male in Abraham's household, including those born in his household or bought from a foreigner, was circumcised with him.
What is the significance of telling us that "on that very day" Abraham circumcised himself and his son and all his servants? This tells us that Abraham obeyed what God told him to do immediately. He didn't wait or try to put it off. Even though it wasn't something painful and he probably didn't want to do it, he had enough faith to obey God.