Source- Dennis T. Olson, Associate Professor of Old Testament, Princeton Theological Seminary-The New Interpreters Bible Commentary
The Book of Judges has three major phases of gradual decline in military effectiveness and religious faithfulness.
First Phase of the Judges Period
Othniel, the model judge (3:7-11), and the two faithful and victorious judges, Ehud (3:12-30) and Deborah (4:1-5:31). Ehud and Deborah had united Israel, defeated the enemy, and praised God for their victories.
Second Phase of the Judges Period
Two major characters stand out. Gideon (6:18-35) and his renegade son Abimelech (9:1-57). Faithfulness to disaster.
The second phase is marked by a transition from victory and faithfulness to idolatry and the reckless and selfish
use of military might and violence.
Gideon‘s initial military victories against the Midianite enemies are impressive, but Gideon is also cowardly, hesitant, and often
doubtful of God’s ability to accomplish what God had promised. Gideon himself shifts from being an idol breaker to an idol maker.
Although Gideon secretly destroys an altar of the pagan god Baal early in his career, he later fashions a golden ephod to obtain oracles from God. The ephod, itself, becomes an object of worship and thus an idol in place of the Lord.
The decline is even more pronounced with Gideon’s son Abimelech (9:1-57). Abimelech’s mother, a Canaanite, was a concubine or a woman servant whom Gideon had taken as a wife. Abimelech declares himself king over Israel after Gideon’s death. Abimelech kills Gideon’s seventy other Israelite sons to solidify his power. Abimelech enlists the support of his mother’s people (Canaanites), the residents of Shechem. Abimelech eventually falls out of favor even with the Shechemites and ends up killing all the inhabitants of Shechem. Finally, Abimelech himself is killed in an ignoble manner as God’s repayment for the disgraceful way in which he ruled over Israel (9:56-57).
Abimelech causes divisions within Israel, kills his own people, and fights for his own honor and glory. Abimelech is a sign that the strategy of leading Israel through the temporary leaders called judges is in serious danger of unraveling.
The rock-The rock is an recurring image that binds together Gideon and Abimelech is that of the rock or stone.
The first rock is the one on which Gideon sets his offering or presents to the angel of God. The angel miraculously causes fire to burn on the rock, consuming Gideon’s offering (6:17-21),. The rock is part of a sign of reassurance to Gideon that God is indeed powerfully present with him as he fights the enemy.
The second rock is the “one stone” on which Abimelech kills the seventy sons of Gideon to protect his arrogant claims to power (9:5, 18).
The third rock (stone) is the millstone that one woman throws from atop the city wall of Shechem onto Abimelech’s head, crushing his skull. Lying half dead next to the millstone, Abimelech orders his servant to kill him with a sword so that the people will not say of Abimelech, ” A woman killed him.” (9:53-54).
The motif of the stone is a divine reassurance for Gideon to the stone as an executioner’s block for the murder of seventy of Abimelech’s half-brothers to a skull-crushing millstone that brings poetic justice onto Amimelech’s head.