Adam Clarke on Job 20:26

A fire not blown shall consume him - As Zophar is here showing that the wicked cannot escape from the Divine judgments; so he points out the different instruments which God employs for their destruction. The wrath of God - any secret or supernatural curse. The iron weapon - the spear or such like. The bow, and its swift-flying arrow.

Darkness - deep horror and perplexity. A fire not blown - a supernatural fire; lightning: such as fell on Korah, and his company, to whose destruction there is probably here an allusion: hence the words, It shall go ill with him who is left in his tabernacle. "And the Lord spake unto Moses and Aaron, Separate yourselves from among this congregation, that I may consume them in a moment. Get ye up from about the tabernacle of Korah, Dathan, and Abiram. Depart from the tents of these wicked men. There came out a fire from the Lord and consumed the two hundred and fifty men that offered incense;" Num 16:20, etc.