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.”
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.” ’ ”
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. 
When we last saw Father Abraham, he was standing on a hilltop overlooking the smoldering Dead Sea Plain as the hill country of Hebron trembled from the great earthquake and ensuing explosions. Abraham had witnessed a ghastly mass extinction of almost all life (human, animal, and vegetation) save one little shaken hamlet. He had yet one more visible demonstration that YHWH, being true to his nature, is faithful to keep his word.
Earlier, God had confirmed his covenant promises to Abram by passing through a bloody covenant path of carved animals. He repeated his promises both in visions and in person. He came in the form of a man and sat down with his angels to eat a covenant meal in front of Abraham and Sarah, promising the birth of Isaac within that year. Now he has destroyed a section of Canaan that was utterly hostile to YHWH and his Promised Seed. So terrifying was his judgment, Abraham packed up his tents, herded all his livestock, packaged all his possessions, and headed south – away from the cursed land.
With its large flocks, numerous slaves and their families, warriors, and wagon loads of goods, Camp Abraham formed an impressive mobile city-state. Wherever Camp Abraham settled, it created competition for resources among the native population and a security threat to local chieftains and kings of neighboring city states. It took great effort to move such a large population of people and livestock and it took delicate political maneuvering to settle peacefully in a new area.
Camp Abraham was far larger and wealthier than it was during the Egyptian sojourn. Moving away from his political allies in Hebron and into another pagan kingdom was huge leap into the unknown. Abraham’s fear of staying so close to the scene of God’s judgment was greater than his fear of the unknown.
The scene of our passage is more than a simple plot twist. It is crucial to understand the nature of God’s relationship with his elect covenant partner Abraham. Though Abraham is yet again unfaithful (like Lot), God remains faithful. He does not throw away his flawed people but restores them to work out his great plan of salvation. This scene forms another chiasm:
A Abimelech takes Sarah into his harem (20:1–2).
B God indicts Abimelech (20:3–7).
X Abimelech and officials become afraid (20:8).
B′ Abimelech indicts Abraham (20:9–13).
A′ Abimelech compensates Abraham and Sarah, and Abraham prays for Abimelech (20:14–18).
SAME SIN, SECOND VERSE (1,2)
While Lot desired to put down roots even if it meant living in a cave tomb east of the Promised Land, Abraham pulled up stakes and set out from Hebron on another pilgrim journey described in here in 20:1. First, he traveled south into the Negev and then spent some time farther south in the line between the oasis of Kadesh and Shur that bordered Egypt in the eastern Nile Delta where it rains less than four inches a year.  Then, Abraham left the Kadesh-Shur grazing area to visit the royal Philistine city of Gerar back north on the fringes of the promised land. The scene ends with Abraham settled in the royal pasturelands around Gerar.
Some commentators and preachers express shock that Abraham again resorts to the same sinful method of self-protection he used while sojourning in Egypt. “2 And Abraham said of Sarah his wife, “She is my sister.” And Abimelech king of Gerar sent and took Sarah.” But you, being made of sterner theological thinking, are not shocked. We recognize in Abraham our default mode of living. We are all hardwired to trust ourselves first and anyone or anything else second. After all, you come every week to hear law and gospel, to receive word and sacrament. God himself shows up to minister to you by his Word and Spirit. He shares his covenantal meal with us. Then, you and I go off and sin again; and again – in thoughts, words, and deeds. That is why, every week, we recite a corporate confession of sin and receive God’s words of absolution. Every week you get an exorcism.
Abraham lived in a place ruled by the world, the flesh, and the devil. It’s the same place in which you and I live. He sojourned through the City of Man, “looking forward to the city that has foundations, whose designer and builder is God.”  Only in the fully realized City of God will we be able to exchange our old sinful Adam 1.0 hardware with the eternal sinless Last Adam 2.0 hardware. Only then will God’s promise to Abraham and all Abram’s seed be fully come: “I will be your God; you shall be my people; I will dwell with you.” The one thing that ought NOT to shock us is that Abraham would sin again by pimping out his wife to another king (an ugly act deserves an ugly word). What ought to amaze us is that God remained loyal to his willfully sinful friend, Abraham!
Not only had Abraham committed this same sin before by pimping out his wife to Pharaoh, he had also received an embarrassing stinging rebuke for it from Egypt’s king. “Why did you not tell me that she was your wife? Why did you say, ‘She is my sister,’ so that I took her for my wife? Now then, here is your wife; take her, and go” (12: 18, 19). That concluding staccato line has just four Hebrew words: “Here . . . wife . . . take . . . go.” Such disdain. The proverb proves true: “Like a dog that returns to his vomit is a fool who repeats his folly.”  Sanctification IS progressive. But it often progresses by two steps forward and one step back.
We each have our own besetting sins, those idols of our default mode that make us feel we are in control of our own destinies. Sins that may not appeal to others have a unique appeal to each one of us. St. Author of Hebrews calls this the “sin which clings so closely.” Abraham’s basic struggle, like all of us, was trusting God.
He believed God’s covenant promise, but in stressful situations he didn’t always apply it. Sometimes Abraham told himself that God needed a little help carrying out his plans. So, yet again, Abraham tells everyone in this new land that Sarah is his sister. Abimelech, Philistine king of the city state of Gerar on the very edge of the Promised Land, takes Sarah into his harem. She is now 90 years old. Unlike Pharaoh’s taking of Sarai in Egypt, this is more likely a political alliance. The king wants no trouble from this powerful Bedouin chieftain. So, he makes Abraham his brother-in-law. Abraham wants no war with a wealthy city state, so he again pimps his wife – the mother of his promised seed due before the end of the year!
GOD’S INDICTMENT (3-7)
Abraham had gotten himself into a bind with his sojourning. He could either live in proximity to the ruthless and powerful pagan king Abimelech or go back over the boarder outside the promised land. Either way, nobody in this area knew who Abraham and Sarah were. He needed to tread carefully. So, yet again, the mother of the promised seed is in jeopardy. From a human perspective, Abraham has put the hope of the entire world in jeopardy! He has threatened the birth of the Promised Seed who was to inherit the world, save a people, and bless them with salvation.
Early in Abram’s story, Sarai was only implicitly the child-bearer and was scarcely mentioned. Even in Pharaoh’s harem, her role in that scene is minor. But since chapter 17, she has taken on a greater part in the story. She’s explicitly mentioned as the mother of the promised seed. YHWH shows up and speaks to her and ratifies his covenant with a meal before her. Now, she will be openly vindicated as innocent in Abraham’s scheme. God loves Sarah and proves himself her Savior.
Abraham moved away from his sacrificial altar at Mamre knowing full well he would be the father to the promised seed within the year (18:10). He proves that “no matter where you go, there you are.” You take your sin with you no matter where you chose to move. But, if you belong to the Lord, he will always prove himself faithful to you. Abraham builds no altar in this new location, but God is there anyway. As David would later sing, “Where shall I go from your Spirit? Or where shall I flee from your presence?” That psalm was sung by the descendant of Abraham, who was worried some king will kill him to take his wife. Isn’t THAT interesting? That’s exactly what David did so many generations later! He killed a man and took his wife.
God does not allow Abraham’s lie to reach its inevitable conclusion. God’s covenant was unilateral, one-sided, unconditional. God is loyal to his covenant even when Abraham is disloyal. This is the essence of grace. God is loyal to the Promised Seed. For the Seed’s sake, Abraham and Sarah are saved.
God shows up in Abimelech’s dream with a terrible pronouncement that literally translated: “You are a dead man because of the woman whom you have taken, for she is a man’s wife.” This is the first of four instances in Genesis in which a covenant outsider receives a dream revelation from God (cf. 31:24—Laban; 40:5—the Egyptian butler and baker; 41:1—Pharaoh). Each of these dreams is a warning dream. Because of general revelation and God’s law written on the hearts of all humanity, people recognize the sacred character of marriage (cf. Lev. 20:22; Deut. 22:22). Adultery was considered a “great sin” among many Semitic groups. That gives us some insight as to how evil the cities of the Dead Sea Plain had become before their destruction. Like Pharaoh, Abimelech knows adultery is wrong.
God had the warrior king’s undivided attention and Abimelech was worried. He responds in defense, “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.” How was Abimelech to know they were married? After all, they had no children. His hands were clean. He had not consummated his relationship with Sarah. But God responds that it is only by his all-powerful, all-knowing will that Abimelech had stayed clear of Sarah. Abimelech was not chivalrous; God was in charge. God commands the king to return Abraham’s wife. “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.” 
The revelation is clear: “You, Abimelech, have your people. I have MY people. These are MY people. Let MY people go or I will kill you and your people.” This is the first use of the word “prophet” in the Bible. In pagan religions, the holiness of a prophet was nearer magic than morality (cf. Num. 22:6). They were the powerful witchdoctors who communed with the demonic realm and acted as personal genies (for a price) to those seeking wish-fulfillment. Abimelech would have seen Abraham as a powerful medicine man, not a spokesperson for the One True God. The king was determined to appease this foreign prophet.
Notice too that, even caught out in his great sin, God gives Abraham duties of ministry. Abraham the sinner, the notorious liar, will serve as an intermediary, an advocate for Abimelech. That should be an encouragement to you sinners who listen to the devil whisper that you are not fit to serve God. Of course, you are not fit! Nor was Abraham fit. Only the perfect life and sacrificial death of the risen and ascended Promised Seed is fit. And he works in you to will and to do the work God gives you. God is the One who does the work. Abraham is merely to pray, to ask God to work.
ABIMELECH’S INDICTMENT (8-13)
Abimelech has been indicted by God. Now it’s Abimelech’s turn to indict Abraham. The pagan king acts with more righteous indignation than God’s righteous prophet, Abraham. Abimelech summoned his courtiers and told them of his dream, striking fear into them as well. Then he called for Abraham. “‘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?’”
Abimelech assumes Abraham, being a prophet, is acting on some vision from a god that wants to unjustly curse the king and all the inhabitants of his kingdom. The gods of the pagans are often mean and petty. But Abraham is not carrying out the will of a malevolent demon; he is merely acting out of cowardice. “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.’”
Some prophet HE is. Had Abraham acted out of trust in YHWH whose prophet he was, he would never had lied. What a horrible and false revelation about the One True God this prophet offered to the pagans by telling half-truths. He didn’t trust that the God he served – who had just broken into the king’s dreams – was truly powerful enough to protect him from the king who turns out to be far more upright and just than Abraham. God’s prophet had affronted the most elementary laws of hospitality.
LOYALTY LOVE (14-17)
Our besetting sins, though they are horrible offenses against our gracious and loyally loving covenant God, never thwart God’s plans. God isn’t shocked by anything he decreed in eternity past, including those times when he removes his protective hand and allows us to pursue our own selfish schemes. He uses our grievous sins as part of our sanctification. He is faithful even in our unfaithfulness. Imagine how ashamed Abraham must have felt to be rightly rebuked by this pagan king. It was God’s way of asking Abraham, “How’s that trusting into your own plans thing working out for you?” Part of growing in holiness is learning to see more of our sins (of thought, word, and deed) and becoming quick to repent of them. So, the apostle John wrote:
This is the message we have heard from him and proclaim to you, that God is light, and in him is no darkness at all. 6 If we say we have fellowship with him while we walk in darkness, we lie and do not practice the truth. 7 But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin. 8 If we say we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. 10 If we say we have not sinned, we make him a liar, and his word is not in us. 
As a further token of God’s loyalty love, Abraham is again showered with wealth by Abimelech. The name “Abimelech” means “The King [god] is my father.” It was a title, like “Pharaoh” was in Egypt. It was a claim to divinity, meaning Abimelech was “The Son of God.” A man claiming to be God’s son showers Abraham with more wealth and openly declares Sarah to be innocent:
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.
Remember when Abram gave Lot the first choice of pastureland? Now, Abimelech gives Abraham that same gracious choice. Two openly guilty people (Sarah confirmed Abraham’s lie, v. 5) were absolved of their crime for which Abimelech should have executed them. Not only were they freed from a just execution, they were declared innocent and given citizenship in the land. No longer were they aliens, but citizens with extraordinary unearned and undeserved wealth and royal protection given by a man with the title “Son of god the king.” The focus of this story is NOT Abraham’s sin (and Sarah’s sin). Their sin is a plot line revealing something FAR greater! The focus of the story is God’s unwavering loyalty love for undeserving sinners for the sake of his Promised Seed.
God alone makes aliens into citizens (“You will be my people.”). He alone cancels the just death sentence being born into Adam’s sin deserves. He alone turns enemies into friends (“I will be your God.”). He alone lavishes upon us the undeserved and infinite wealth of a living relationship with him (“I will dwell with you.”) And he does it simply because it pleases him to do so – NOT because of any human goodness or merit. He does it because he is loyal to his covenant with Abraham to bring the Promised Seed, the true Son of God.
Abimelech’s blessings were given to Abraham and Sarah out of fear and self-interest. The blessings of God through Christ the Promised Seed flow freely and solely out of his covenant love.
In this is the love, not that we ourselves have been loving him but that he himself has loved us and sent out his Son – a propitiation for our sin.
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Ge 20:1–18.
 Waltke and Fredricks, 283.
 Waltke and Fredricks, 284.
 Hughes, 285-286. Kindle Edition.
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Heb 11:10.
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Pr. 26:11.
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Heb 12:1.
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Ps 139:7.
 Hughes, 287. Kindle Edition.
 Hamilton, 2:60.
 Waltke and Fredricks, 285–286.
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Ge 20:7.
 Kidner, 1:148.
 The Holy Bible: English Standard Version (Wheaton, IL: Crossway Bibles, 2016), 1 Jn 1:5–10.
 1 Jn. 4:10. Trans. mine. Emphasis mine.