Thomas Aquinas

One can consider walking without deceit by inspecting the righteousness of justice from which the deceitful man turns aside, and so he says, "let him (God) weigh me in a just balance," to discern from his justice if I have proceeded in deceit. Since deceit consists especially in the intention of the heart, he alone can judge deceit to whom the intention of heart lies open, namely God. So he then says, "and let God know my simplicity," which is the contrary of the duplicity of deceit. …

Commentary on Job ↗