Genesis 11 paints a pretty hopeless picture. The new, post flood humanity have in effect squandered the blessings and privileges of the covenant with Noah. Their hubristic rebellion against God has been crushed, they are divided by language and scattered across the world of the day. However, at the end of the chapter, we are encouraged to focus in on one family, Terah’s clan who have moved away from the centre of civilisation in Ur (close to Babel) and settled in a place called Haran, just north of modern-day Israel (Genesis 11:27-31).
Terah’s son is called Abram, meaning “father of a people or nation” which is ironic because Abram and his wife are childless. There still doesn’t appear to be much hope but into that situation God speaks. Genesis 12 begins with God calling Abram.
The Call (Genesis 12:1-9)
God appears to Abram. He has been living in Haram with his father’s family having moved from Ur. This takes us back to the time before Terah had died as recorded at the end of chapter 11. Goldingay suggests that this functions to emphasis that even if chronologically this happened whilst Abram’s father was alive, this marks a new start. Abram takes on the responsibilities of being head of his own people. “Terah and his decision making are the past. He’s dead even though he is alive.”
God is named as YHWH here. God speaks to Abraham and commands him to leave his Father’s family and the land where has settled. God will show him the land where he is to settle and live. Note that the command is to “go by yourself.” Haram had been a temporary stopping off point away from the spiritual dangers of idolatrous Ur. However, just as Noah had to move on from the Ark in order to enter into covenant relationship with God, so too must Abram leave his temporary abode. The biggest sacrifice for Abram would be leaving behind family/clan as his immediate attachment was not to Haran but to Ur (v1) .
The command comes with a threefold promise. God will create a great and mighty nation from Abraham, he will make his name great and he will bless him. Wenham comments that “What modern secular man calls ‘luck’ or ‘success‘, the OT calls ‘blessing’, for it insists that God alone is the source of all good fortune.”  Here is the antidote to Babel. V2 “The tower builders in chapter 11 wanted to make a name for themselves but succeeded only in a way they didn’t intend. Yahweh himself will do it for the person who isn’t seeking it” (v2). 
The promise is also that those who bless Abram, who treat him well and respect him will be blessed by God. Those who curse him and seek him harm will come under God’s curse. The words used for cursing are slightly different in Hebrew. Literally, it is the ones who dishonour, make light of or disdain Abram who are cursed. Those who mock him may think it a light matter but God does not treat disdain for his people lightly. Those who belittle those who belong to him will be subject to the full force of judgement. There is a parallel here with what happens to Noah at the hands of Ham and the subsequent cursing of Canaan. This is significant given that the Canaanites are in the land but God will not allow them to shame and disdain Abram.  In essence God offers Abraham provision, protection and status/honour. We can also see the typology of Land/People/Blessinghere (v3).
Abram obeys God and heads towards Canaan. Lot his nephew accompanies him. At 75 he is approaching later life, even allowing for a longer age span in those days (v4). He is obviously prosperous so that his wealth is worth mentioning but notice the repetition that it is his nephew, Lot, who goes with him (v5). This repetition emphasises the point that despite being promised descendants, Abram at this point lacks an heir. It is presumed that Lot will succeed him at this stage. He arrives in and passes through the land, he is beginning to survey his inheritance, claiming ownership but that right is contested because there are prior claimants, the Canaanites who already live there. Remember that the Canaanites “are under God’s curse (Genesis 9:25) and due to be Shem’s servants (Genesis 9:26-27)” (v6). 
It’s against a backdrop of faith and uncertainty then that God repeats the promise of offspring to Abram. Abrams’s response is to demonstrate his trust in God with worship as he builds an altar (v7). He then goes on to build altars at other sites, Bethel and Ai, in effect setting out his borders (v8). However, there’s also tension because he doesn’t appear to be stopping, he continues to journey south towards Egypt (v9).
Threat (Genesis 12:10 -14:24)
Things do not pan out straightforwardly for Abram. He has arrived in the land promised him by God but he is still without an heir, the land is occupied by rivals to his people and soon, drought and famine come. Abram flees to Egypt and there Pharoah takes a fancy to his wife, Sarah. In order to protect them both, Abram attempts to pass Sarah off as his sister but this leads to further danger as God brings judgement upon Pharoah. I suspect that for all the game playing on Abram’s part that the story that Sarah was his sister would have obviously lacked credibility to a King who was more concerned for integrity and less for satiating his own immediate desires. So, we see an early demonstration of God’s curses coming against those who show disdain for Abram (Genesis 12:10-20).
Abram returns to the land, blessed with greater wealth but there are further struggles ahead, His men get into conflict with Lot’s servants over scarce resources and so the two men agree to go their own separate ways. Abram, in an act of faith, allows Lot to choose where he will settle first and the nephew chooses the seemingly more prosperous and fertile region around Sodom and Gomorrah. This separation also makes it clear that Lot is not to be Abram’s heir (Genesis 13:1-18).
Covenant (Genesis 15:1-6)
God appears to Abram again at the start of Genesis 15. following everything that he has been through including his attempt to seek haven in Egypt and his separation from Lot. He encourages him to not fear. YHWH will be his shield and will reward him for his faithfulness. This is a promise again of provision and protection (v1).
Abram’s response is to question God at first. The promise seems impossible. God may reward him with land and wealth but this is pointless because he lacks an heir. Options have narrowed since the split with Lot. It is not even possible for someone from his bloodline to inherit, no close relative. Instead, one of his household stewards will have to be adopted into the family and receive everything (v2-3).
God insists that Eleazor of Damascus will not be Abram’s heir. It will be a physical descendent. Despite it seeming impossible God insists that children and grandchildren are coming (v4). To emphasise his point, God takes Abram outside and tells him to gaze up to the heavens and have a go at counting the stars. Of course, that would be impossible. God’s point is that just as the stars are countless, so will be the multitudes of descendants to follow after Abram. God will bless him, not just with land and wealth but with a people, a nation (v5).
Abram believes. He accepts that God’s word is true and he trusts him to keep his promise. We are told that God counted this as righteousness, he reckoned righteousness to Abram’s account. Paul will use this in Romans 4:1-8 to show that righteousness or justification is received from God not by keeping the rules in The Law but through faith (v6).
The promised reaffirmed (Genesis 17:1-7)
Abram’s life story continues with further challenges and failings as well as evidence of faith. A marker of failure is when in desperation to resolve the line of succession, his wife arranges for him to sleep with one of her servants, Hagar. This leads to the birth of Ishmael and generations of conflict to follow. God does not give up on him but speaks to him again in chapter 17.
Abram is now ninety-nine years old, a full 24 years after he had first responded to God’s call. God appears to him again. This time he chooses to use another name to reveal himself, El -Shaddai, God Almighty. The name refers to God as exalted and lifted up high. He tells Abram to “walk before me. “ In other words, he is to live in God’s presence and in God’s sight. He is to live life knowing that God can see everything he does. This means that he should seek to be blameless. The call to blameless righteousness links him back to another Covenant recipient, to Noah. However, “for Noah, blameless is an accomplished fact …while for Abraham it is a goal.” We must remember though that Abraham has already been declared righteous through faith. Blameless obedience is to be the fruit of his justification and blessing, not the cause of it. (v1) Why is he to do this? Well, it’s because God desires to make his covenant with him (v2). Once again, there is a promise of descendants. Abram prostrates himself to worship God (v3).
God states again the nature of his covenant with Abram, it is to give him descendants, he is going to be the ancestor, founder, father to nations. Note, this will be many nations not just the one (v4). To symbolise this and confirm it, God changes Abram’s name. Just as the covenant God, Yahweh had presented himself as the exalted God, so now, through his covenant with Abram, he will exalt the man. This childless old man’s new name is Abraham, father of a multitude of peoples (v5). God promises him fruitfulness. Bruggeman observes that:
“Thus Abraham is the first fruit of the new creation. He is the bearer of what is intended in creation. He is indeed the new creation.”
Not only will his descendants be numerous but they will be influential and powerful. There will be kings and rulers among them. Here we see an echo to the blessing and command of Genesis 1:26-28. Abraham’s descendants will be fruitful and multiply. They will fill the land which God has given him and they will rule and subdue it (v6). God’s covenant commitment is not just to Abraham, it is for his descendants too. It is a permanent, eternal covenant. This of course sets up a crucial future question, if this is a covenant for Abraham’s descendants and is permanent then, it has not been overturned. Who then are the rightful heirs of Abraham? (v7).
Tested (Genesis 22)
Eventually a son arrives, as God had persistently promised. Then one day God puts Abraham to the test. He tells him to:
“Take your son, your only son—yes, Isaac, whom you love so much—and go to the land of Moriah. Go and sacrifice him as a burnt offering on one of the mountains, which I will show you.”
Abraham proves faithful. The question is whether or not he can really and fully trust God to provide. The clear answer from his response in obeying is that he does trust God to provide and protect, even if the way that God will keep his promises is going to be through death and resurrection. God provides a substitute sacrifice, a ram.
However, I want to draw your attention to the way that Isaac is described in verse 2. He is Abraham’s only son and his beloved son. Here is a little cue of things to come as Isaac’s description prefigures the way that John 3:16 will present Jesus as God’s only and beloved son, presented as the perfect sacrifice for all.
Once again, the promise is re-affirmed. God tells Abraham.
16 … Because you have obeyed me and have not withheld even your son, your only son, I swear by my own name that 17 I will certainly bless you. I will multiply your descendants[a] beyond number, like the stars in the sky and the sand on the seashore. Your descendants will conquer the cities of their enemies. 18 And through your descendants all the nations of the earth will be blessed—all because you have obeyed me.”
Genesis 12 marks the turning point in Genesis. The story so far has been about human rebellion and the trashing of God’s creation. Here in Genesis 12 we see God’s loud and clear declaration that he has not finished with humanity.
God had committed back in Genesis 1:26-28 to bless humanity and to make Adam and Eve fruitful. God had called on humankind to fill and subdue creation. However, through these first chapters we see that because of sin, humanity resists both the command and the blessing. There is a resistance against being fruitful and multiplying as Cain murders his brother, there is a resistance to spreading out and filling creation as seen in Genesis 11. Even when humanity does multiply, it fills and subdues the earth not with goodness and God’s reign but with evil (Genesis 6). Yet, the message of Genesis 12-22 is that God is not done with humanity. His plan is still to be the one who calls a people to himself, blesses them and sends them out to rule over creation. The promise is now focused on one man and his family in one place. This man Abraham embodies the hopelessness of humanity with the curse of death upon him and his wife through infertility. Yet, to the God who is the author of life, this is no barrier. God is able to bring life from death and to do the impossible. God is able to bring blessing where there is curse. There is still hope.
 Goldingay, Genesis, 206.
 C.f. Hamilton, Genesis 1-17, 371.
 Wenham, Genesis 1-15, 274.
 Wenham, Genesis 1-15, 275.
 Goldingay, Genesis, 208. C.f. Hamilton, Genesis, 372.
 Wenham, Genesis 1-15, 276.
 Goldingay, Genesis, 208.
 C.f. Hamilton, Genesis 1-17, 376.
 Goldingay, Genesis, 211.
 Though this is really more to reinforce a point already made in Genesis 12:7. C.f. Hamilton, Genesis 1-17,377.
 “This phrase usually expresses the faithful service of a servant to their king.” Hamilton, Genesis 1-17, 461.
 Hamilton, Genesis1-17, 461.
 Brueggemann, Genesis, 153.
 Genesis 22:2.
 Genesis 22:17-18