What does Judges 4:21 mean?
Within the flow of this story, this verse is sudden and shocking. We simply do not see it coming. Ehud's assassination of Eglon (Judges 3:21–22) was gory and brutal, but clearly foreshadowed by mentions of Ehud's hidden weapon (Judges 3:16). This violence comes out of nowhere; Jael instantly pivots from gracious hostess to brutal killer.The unexpected executioner asked Sisera, the fleeing commander of Jabin's Canaanite army (Judges 4:15–17), to come into a tent to hide from the pursuing Israelites. Her husband Heber (Judges 4:11) had a peace agreement with Jabin (Judges 4:18–19). Sisera had multiple reasons to assume he would be safe from harm with Jael standing guard.
Jael's family group is nomadic, and women were responsible for setting up and taking down tents. She would have been very comfortable with handling a hammer and spikes. Tents were a combination of coverings and posts, anchored to the ground using "pegs." In this context, a tent peg was a sharp wooden spike about 12 inches, or 30 centimeters, in length and about 1 inch, or 25 millimeters, in diameter.
As soon as the general has fallen asleep, Jael sneaks up to him with a tent peg and a mallet—probably a wooden hammer. She selects the soft spot on the side of the skull, in the area between the eye, ear, and forehead. She then hammers the spike through the general's skull and into the ground below. It's not likely she delivered a single impact: the spike is driven entirely through Sisera's head and into the dirt. Brutal as it sounds, Sisera's death was probably quick; it's possible he never knew what happened.
The verse ends with a phrase so obvious that it's likely included only for the sake of poetry and irony: "so he died."
Jael's motives are never clearly stated. Whether her husband was friendly to men like Sisera or not, clearly Jael shared the views of the Kenite people, who at that time were no friend of the Canaanites. Sisera's reputation for treatment of women was poor (Judges 5:30). Perhaps she favored the Israelites for some reason? Some scholars suggest Jael worried that her helping Sisera might put the household in danger when the Israelites found him. She may have simply been protecting herself and her people. As is the case with many such events, the Bible does not indicate that God inspired Jael's actions. Nor does it indicate that what she did was, necessarily, a moral choice. It simply notes "what" she did, without much commentary on why or whether it was really the best course of action.
Whatever her reasons, Jael will not attempt to hide Sisera's corpse from Barak or the Israelites. Scripture doesn't indicate how long it took Barak to come by after annihilating the Canaanite army (Judges 4:22), but it likely was no more than several hours. When his forces near, Jael will immediately make her actions known.
