Fausset's Bible Dictionary

1. Hence, we find Achish called Abimelech in the title of Psalm 34, which explains the seeming discrepancy of name in 1Sa 21:11.

2. Gen 20:1, 1898 B.C.; Hales, 2054 B.C.: the king of Gerar. Abimelech's taking Sarah into his harem shows that in those times kings claimed the odious despotic right of taking unmarried females, whether subjects or sojourners; compare Gen 12:15; Est 2:3. A divine warning that death would be the penalty of keeping her, but that Abraham's intercession as a prophet would follow the restoring of her, led him to give her back with a present of a thousand pieces of silver (131 British pounds). With delicate sarcasm (in the English KJV) he reproved Abraham's deception.

Rather, as Keil and Delitzsch, instead of "he," translate "this is to thee a covering of the eyes (i.e. an expiatory gift) with regard to all that are with thee" (because in a mistress the whole family is disgraced), "so thou art justified." The closing of the wombs of Abimelech's house then ceased. Abimelech some years after repaired, with Phichol his chief captain, to Abraham to form a treaty of friendship. He restored the well dug by Abraham, but seized by Abimelech's herdsmen. It was thence named Beersheba, the well of the oath, and consecrated to Jehovah (Gen 21:22-34).

So by loving concession shall we find peace and room at last (Rom 12:18-21; Joh 14:2; Psa 31:8; Psa 118:5). At Beersheba Abimelech with Ahuzzath his friend, and Phichol his captain, renewed the treaty of friendship with Isaac, originally made by his father with Abraham, and for the same reason (notwithstanding his past bad treatment of Isaac in sending him away), namely, he saw the Lord was with Isaac. Compare Gen 26:23 with Gen 21:22-23. Plainly the Philistines had then a more organized government than the Canaanite nations, one of which had been supplanted by these foreign settlers.

4. Son of Gideon by his Shechemite concubine (Jdg 8:31). At Gideon's death he murdered his seventy brethren, excepting the youngest, Jotham, who hid himself, and by his mother's brethren influenced the Shechemites to make him king. Then Jotham addressed to the Shechemites the fable of the trees and the bramble (Judges 9), presaging a feud between Abimelech and Shechem which would mutually consume both. So it came to pass; for God makes in righteous retribution the instruments of men's sin the instrument also of their punishment at last. After three years Shethem rebelled, under Gaal. At Zebul's information Abimelech came rapidly on the rebels and slew all, and beat down their city, and sowed it with salt; he burned to death a thousand more men and women who fled for sanctuary to the hold of the idol Baalberith. Thence he marched to Thebez, nine miles eastward, and took the town; but when trying to burn the tower was struck on the head by a piece of a millstone cast down by a woman. Feeling his wound mortal, he was slain by his armorbearer, at his own request, lest it should be said a woman slew him. For the spiritual lesson read Jer 2:19; Pro 5:22; Pro 1:31; Job 20:5; Mat 26:52. The friendship that is based on sin is hollow; compare 2Sa 13:3-5; 2Sa 13:32-33.