Proverbs 22:8

He that soweth iniquity shall reap vanity: and the rod of his anger shall fail.

Sowing iniquity means persisting in doing evil. Professing godliness while acting against God does not alter that reality, but is itself still such sowing. Saying that evil conduct is simply one's nature or way does not excuse it from being the sowing condemned.

The warning is that pride in prosperity leads to this sowing, when early humility gives way after wealth and worldly honor arrive. Then God is forgotten as the Source of prosperity, and that forgetting perverts the heavenly gifts of wealth and influence to selfish purposes. Profligacy accompanied by extravagance is the wrongdoing that brings the empty harvest, such as building a magnificent palace of costly stones within and without from foundation to coping for Pharaoh's daughter and spending thirteen years building one's own house. Those who so sow will reap emptiness and destruction, with pride of prosperity ending in apostasy.