Charles Ellicott Commentary Judges 8:16

"And he took the elders of the city, and thorns of the wilderness and briers, and with them he taught the men of Succoth." — Judges 8:16 (ASV)

He taught. —Literally, made to know (Proverbs 10:9); but דע may be a misreading for ישׂ “he threshed,” as in Judges 6:7. (Vulgate contrivit atque comminuit.)

The men of Succoth. — i.e., the elders. Gideon would be well aware that in an eastern city the mass of the people have no voice in any decision. Ewald takes it to mean, “By them (the slain elders) he taught the (rest of the) people of Succoth to be wiser in future.”