John Gill Commentary Psalms 58:2

"Nay, in heart ye work wickedness; Ye weigh out the violence of your hands in the earth." — Psalms 58:2 (ASV)

Yea, in heart you work wickedness
So far were they from speaking righteousness, and judging uprightly. The heart of man is wickedness itself; it is desperately wicked, and is the shop in which all wickedness is wrought; for sinful acts are committed there as well as by the tongue and hand, as follows.

This phrase also denotes their sinning; not with precipitancy, and through surprise; but with premeditation and deliberation; and their doing it heartily, with good will, and with allowance, and their continuance and constant persisting in it;

you weigh the violence of your hands in the earth ;
they were guilty of acts of violence and oppression, which, of all men, judges should not be guilty of; whose business it is to plead the cause of the injured and oppressed, to right their wrongs, and to protect and defend them:

these they pretended to weigh in the balance of justice and equity, and committed them under a show of righteousness; they decreed unrighteous decrees, and framed mischief by a law; and this they did openly, and everywhere, throughout the whole land.