All the ways of a man are clean in his own eyes (Proverbs 21:2). He may deceive himself, and be blind to his own faults, or be following an ill-informed and ill-regulated conscience (Proverbs 12:15; Proverbs 14:12), yet this is no excuse in God's eyes.
The Lord weigheth the spirits. Not the "ways," the outward life and actions only, but motives, intentions, dispositions (Hebrews 4:12). He too knows our secret faults, unsuspected by others, and perhaps by ourselves (Psalms 19:12).
The Septuagint has here, "All the works of the humble are manifest before God, but the impious shall perish in an evil day." The next verse is omitted in the Greek; and the other clauses up to Proverbs 16:8 are dislocated.