17 Meanwhile, Sisera ran to the tent of Jael, the wife of Heber the Kenite, because Heber's family was on friendly terms with King Jabin of Hazor. 18 Jael went out to meet Sisera and said to him, "Come into my tent, sir. Come in. Don't be afraid." So he went into her tent, and she covered him with a blanket. 19 "Please give me some water," he said. "I'm thirsty." So she gave him some milk from a leather bag and covered him again. 20 "Stand at the door of the tent," he told her. "If anybody comes and asks you if there is anyone here, say no." 21 But when Sisera fell asleep from exhaustion, Jael quietly crept up to him with a hammer and tent peg in her hand. Then she drove the tent peg through his temple and into the ground, and so he died.
Matthew Henry's Commentary on Judges 4:17-21
Commentary on Judges 4:17-24
(Read Judges 4:17-24)
Sisera's chariots had been his pride and his confidence. Thus are those disappointed who rest on the creature; like a broken reed, it not only breaks under them, but pierces them with many sorrows. The idol may quickly become a burden, Isaiah 46:1; what we were sick for, God can make us sick of. It is probable that Jael really intended kindness to Sisera; but by a Divine impulse she was afterwards led to consider him as the determined enemy of the Lord and of his people, and to destroy him. All our connexions with God's enemies must be broken off, if we would have the Lord for our God, and his people for our people. He that had thought to have destroyed Israel with his many iron chariots, is himself destroyed with one iron nail. Thus the weak things of the world confound the mighty. The Israelites would have prevented much mischief, if they had sooner destroyed the Canaanites, as God commanded and enabled them: but better be wise late, and buy wisdom by experience, than never be wise.