For it is a fire that consumeth to destruction; i.e. it is a thing which brings down the wrath of God upon a man, so that "a fire is kindled in his anger, which shall burn unto the lowest hell" (Deuteronomy 32:22).
Compare the sentence on David for his great transgression (2 Samuel 12:9-12). And would root out all mine increase; i.e. "would destroy all my estate;" either by leading me to waste my substance upon my companion in sin, or by bringing down God's judgments upon me to my temporal ruin.