From Genesis 19-21
Gen 19.1-23; Story; God rescues Lot and his family from Sodom
Gen 19.33-29; Story; God destroys Sodom
Gen 19.30-38; Story; Lots daughters sleep with Lot to continue their family lines
Gen 20.1-18; Story; Abraham does not say Sarah is his wife and God protects
Gen 21.1-7; Story; God is faithful and Isaac is born
Gen 21.8-21; Story; God protects Hagar and Ishmael after Abraham and Sarah removed them
Gen 21.22-34; Story; Abraham makes a covenant of peace with Abimelech
Passage and Comments
The LORD has made some significant promises to Abraham (blessings, offspring, land). Abraham's faith in the LORD and his promises does not guarantee a rosy life however and sometimes Abraham makes some questionable decisions.
The story concerning Abraham picks up after God has reiterated his promise that he and Sarah will have a son (Gen 18.1-15). The LORD tells Abraham his plans for Sodom and Abraham intercedes as we saw yesterday. Lot and his family (with one exception) are rescued and Sodom gets blasted (Gen 19.1-29).
Lets consider the implications of God's promise and the age of both Abraham and Sarah. Sarah 90 years old when the promise of offspring is reiterated (Gen 17.17,21). Sarah therefore has Isaac when she is 91. Abraham is 100 years old when Isaac is born (Gen 21.5). A 9 year difference. (I've heard of this formula for dating. The youngest age of a women a man can pursue is half his age + 7; Abraham is close to 100. So 100/2 = 50 + 7 = 57 lowest female age. Abraham 100 and Sarah at 91 is fine.) Moving on, imagine a 90/99 year old couple having sex. The text says Sarah is a looker (Gen 12.11). Okay don't go there. Try instead imagining one year later the woman having a baby at 91 years of age. Hmmm. Seriously, God's faithfulness to his promise of offspring = Miracle.
Lets look at the passage.
20 From there Abraham journeyed toward the territory of the Negeb and lived between Kadesh and Shur; and he sojourned in Gerar. 2 And Abraham said of Sarah his wife, “She is my sister.” And Abimelech king of Gerar sent and took Sarah. 3 But God came to Abimelech in a dream by night and said to him, “Behold, you are a dead man because of the woman whom you have taken, for she is a man’s wife.” 4 Now Abimelech had not approached her. So he said, “Lord, will you kill an innocent people? 5 Did he not himself say to me, ‘She is my sister’? And she herself said, ‘He is my brother.’ In the integrity of my heart and the innocence of my hands I have done this.” 6 Then God said to him in the dream, “Yes, I know that you have done this in the integrity of your heart, and it was I who kept you from sinning against me. Therefore I did not let you touch her. 7 Now then, return the man’s wife, for he is a prophet, so that he will pray for you, and you shall live. But if you do not return her, know that you shall surely die, you and all who are yours.” (Gen 20.1-7 ESV)
Abraham's logic behind these actions is explained in Gen 12.11-13. From his point of view, if he says she is his sister his life will be spared. It is possibly easy to condemn Abraham here, but I read something Augustine of Hippo said once which argues strongly against this view.
8 So Abimelech rose early in the morning and called all his servants and told them all these things. And the men were very much afraid. 9 Then Abimelech called Abraham and said to him, “What have you done to us? And how have I sinned against you, that you have brought on me and my kingdom a great sin? You have done to me things that ought not to be done.” 10 And Abimelech said to Abraham, “What did you see, that you did this thing?” 11 Abraham said, “I did it because I thought, ‘There is no fear of God at all in this place, and they will kill me because of my wife.’ 12 Besides, she is indeed my sister, the daughter of my father though not the daughter of my mother, and she became my wife. 13 And when God caused me to wander from my father’s house, I said to her, ‘This is the kindness you must do me: at every place to which we come, say of me, “He is my brother.” ’ ” (Gen 20.8-13 ESV)
God shows himself to be with Abraham. Abimelech confronts Abraham. Abraham explains himself. Note to self - don't mess with God's people.
14 Then Abimelech took sheep and oxen, and male servants and female servants, and gave them to Abraham, and returned Sarah his wife to him. 15 And Abimelech said, “Behold, my land is before you; dwell where it pleases you.” 16 To Sarah he said, “Behold, I have given your brother a thousand pieces of silver. It is a sign of your innocence in the eyes of all who are with you, and before everyone you are vindicated.” 17 Then Abraham prayed to God, and God healed Abimelech, and also healed his wife and female slaves so that they bore children. 18 For the LORD had closed all the wombs of the house of Abimelech because of Sarah, Abraham’s wife. (Gen 20:14–18 ESV)
It seems the LORD had been done more than just give Abimelech a dream. His household was being afflicted as well. If we skip a little forward Abimelech makes a revealing observation about Abraham.
 At that time Abimelech and Phicol the commander of his army said to Abraham, “God is with you in all that you do.  Now therefore swear to me here by God that you will not deal falsely with me or with my descendants or with my posterity, but as I have dealt kindly with you, so you will deal with me and with the land where you have sojourned.”  And Abraham said, “I will swear.” (Gen 21:22-24 ESV)
The word on the street is that God is with Abraham and people are noticing.
Story of Jesus
Story of Jesus
Paul once said;
31 What then shall we say to these things? If God is for us, who can be against us? 32 He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things? 33 Who shall bring any charge against God’s elect? It is God who justifies. 34 Who is to condemn? Christ Jesus is the one who died—more than that, who was raised—who is at the right hand of God, who indeed is interceding for us. 35 Who shall separate us from the love of Christ? Shall tribulation, or distress, or persecution, or famine, or nakedness, or danger, or sword? 36 As it is written,
“For your sake we are being killed all the day long;
we are regarded as sheep to be slaughtered.”
37 No, in all these things we are more than conquerors through him who loved us. 38 For I am sure that neither death nor life, nor angels nor rulers, nor things present nor things to come, nor powers, 39 nor height nor depth, nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord. (Rom 8:31–39 ESV)
What a great comfort it is to know is if God is for us, none can be against us. Secondly, looking at Abraham there are times when it is clear despite how well we trust God or how we treat others. When I see Abraham act like this I'm reminded of the grace, mercy and loyalty God has for his people.
Today God's people are those who know Jesus as their Lord. As we walk through life as Abraham did let us consider God's faithfulness to us and his overlooking our own questionable actions. I'm sure if we did that more and more, we would seek to please him as we should.