All the words of my mouth are in righteousness; there is nothing froward or perverse in them. All the words - are in righteousness - בצדק betsedek, in justice and equity, testifying what man owes to his God, to his neighbor, and to himself; giving to each his due. This is the true import of צדק tsadak.
There is nothing froward - נפתל niphtal, tortuous, involved, or difficult.
Or perverse - עקש ikkesh, distorted, leading to obstinacy. On the contrary,