Genesis 20:3

After the destruction of Sodom and Gomorrah, Abraham removed from the grove of Mamre at Hebron to the south country, hardly from the same fear as that which led Lot from Zoar, but probably to seek for better pasture. Here he dwelt between Kadesh (Gen 14:7) and Shur (Gen 16:7), and remained for some time in Gerar, a place the name of which has been preserved in the deep and broad Wady Jurf el Gerr (i.e., torrent of Gerar) about eight miles S.S.E. of Gaza, near to which Rowland discovered the ruins of an ancient town bearing the name of Khirbet el Gerr. Here Abimelech, the Philistine king of Gerar, like Pharaoh in Egypt, took Sarah, whom Abraham had again announced to be his sister, into his harem, - not indeed because he was charmed with the beauty of the woman of 90, which was either renovated, or had not yet faded (Kurtz), but in all probability "to ally himself with Abraham, the rich nomad prince" (Delitzsch). From this danger, into which the untruthful statement of both her husband and herself had brought her, she was once more rescued by the faithfulness of the covenant God. In a dream by night God appeared to Abimelech, and threatened him with death (מת הנּך en te moriturum) on account of the woman, whom he had taken, because she was married to a husband.

It appears by this that God revealed himself by dreams (which evidenced themselves to be divine and supernatural) not only to his servants the prophets, but even to those who were out of the pale of the church and covenant; but then, usually, it was with some regard to God's own people as in Pharaoh's dream, to Joseph, in Nebuchadnezzar's, to Daniel, and here, in Abimelech's, to Abraham and Sarah, for he reproved this king for their sake, Psa 105:14, Psa 105:15. I. God gives him notice of his danger (Gen 20:3), his danger of sin, telling him that the woman is a man's wife, so that if he take her he will wrong her husband; his danger of death for this sin: Thou art a dead man; and God's saying so of a man makes him so. Note, Every wilful sinner ought to be told that he is a dead man, as the condemned malefactor, and the patient whose disease is mortal, are said to be so. If thou art a bad man, certainly thou art a dead man. II. He pleads ignorance that Abraham and Sarah had agreed to impose upon him, and not to let him know that they were any more than brother and sister, Gen 20:6. See what confidence a man may have towards God when his heart condemns him not, Jo1 3:21. If our consciences witness to our integrity, and that, however we may have been cheated into a snare, we have not knowingly and wittingly sinned against God, it will be our rejoicing in the day of evil. He pleads with God as Abraham had done, Gen 18:23. Wilt thou slay a righteous nation? Gen 20:4. Not such a nation as Sodom, which was indeed justly destroyed, but a nation which, in this matter, was innocent. III. God gives a very full answer to what he had said. 1. He allows his plea, and admits that what he did he did in the integrity of his heart: Yea, I know it, Gen 20:6. Note, It is matter of comfort…

20:3-7 God gave Abimelech a stern warning against committing adultery; it was a capital offense (cp. Exod 20:14), viewed throughout the ancient Near East as a “great sin” (Gen 20:9). 20:3 that night God came . . . in a dream: God urgently intervened to stop Abimelech from violating Sarah’s purity shortly before God’s promise was fulfilled (18:10; 21:1-3).