Albert Barnes Commentary Ezekiel 39:9-10

"And they that dwell in the cities of Israel shall go forth, and shall make fires of the weapons and burn them, both the shields and the bucklers, the bows and the arrows, and the handstaves, and the spears, and they shall make fires of them seven years; so that they shall take no wood out of the field, neither cut down any out of the forests; for they shall make fires of the weapons; and they shall plunder those that plundered them, and rob those that robbed them, saith the Lord Jehovah." — Ezekiel 39:9-10 (ASV)

Burn them with fire - Or, “kindle fire with them;” or, as in the margin. The weapons of the army left on the field of battle will be so numerous as to supply fuel for the people of the land for seven years. Seven was a number connected with cleansing after contact with the dead (Numbers 19:11 and following), and this purification of the land by the clearance of pagan spoils was a holy work .