Sisera called out all his chariots, 900 chariots of iron, and all the men who were with him, from Harosheth-hagoyim to the river Kishon.
Here, I. Barak beats up for volunteers, and soon has his quota of men ready, Jdg 4:10. Deborah had appointed him to raise an army of 10,000 men (Jdg 4:6), and so many he has presently at his feet, following him, and subject to his command. God is said to call us to his feet (Isa 41:2), that is, into obedience to him.
Commenting on Judges 4:10-16
And Sisera gathered together all his chariots,.... Or "therefore" he gathered them together, which might lie some in one place, and some in another, for the better quartering of the men that belonged to them: even nine hundred chariots of iron; and which, as before observed, are magnified by Josephus, and made to be three thousand: and all the people that were with him; his...
the river of Kishon--The plain on its bank was chosen as the battlefield by Sisera himself, who was unconsciously drawn thither for the ruin of his army.