Charles Ellicott Commentary Judges 8:9

"And he spake also unto the men of Penuel, saying, When I come again in peace, I will break down this tower." — Judges 8:9 (ASV)

When I come again in peace. —Compare to 1 Kings 22:27.

I will break down this tower. —If the strength of their citadel emboldened them to refuse food to Gideon’s fainting warriors, it would also have helped to protect them against the dreaded vengeance of Midian.