For the LORD shall rise up as in mount Perazim, he shall be wroth as in the valley of Gibeon, that he may do his work, his strange work; and bring to pass his act, his strange act.
Perazim - in the valley of Rephaim (2 Samuel 5:18; 2 Samuel 5:20; 1 Chronicles 14:11); there Yahweh, by David, broke forth as waters do, and made a breach among the Philistines, David's enemies, as Pªratsiym (H6559) means; expressing a sudden and complete overthrow.
As (in) the valley of Gibeon - David's slaughter of the Philistines "from Gibeon even to Gazer," (1 Chronicles 14:16; 2 Samuel 5:25, margin) Or, as the Chaldaic, which the reference to "hail" confirms, Joshua's victory at Gibeon over the five confederate kings, whereby rest was given to the land. On that occasion, as here, the Lord cast down great hailstones from heaven upon the enemy (Joshua 10:10).
His strange work - strange, as being against His own people. Judgment is not what God delights in: it is, though necessary, yet strange to Him (Lamentations 3:33).
Work - punishing the guilty (Isaiah 10:12).