Proverbs 20:9
7 The righteous person behaves in integrity; blessed are his children after him. 8 A king sitting on the throne to judge separates out all evil with his eyes. 9 Who can say, “I have kept my heart clean; I am pure from my sin”? 10 Diverse weights and diverse measures—the Lord abhors both of them. 11 Even a young man is known by his actions, whether his activity is pure and whether it is right.
1 John 1:8
6 If we say we have fellowship with him and yet keep on walking in the darkness, we are lying and not practicing the truth. 7 But if we walk in the light as he himself is in the light, we have fellowship with one another and the blood of Jesus his Son cleanses us from all sin. 8 If we say we do not bear the guilt of sin, we are deceiving ourselves and the truth is not in us. 9 But if we confess our sins, he is faithful and righteous, forgiving us our sins and cleansing us from all unrighteousness. 10 If we say we have not sinned, we make him a liar and his word is not in us.
Notes and References
"... Once his concession is made, he returns to his exhortation to challenge the "brothers [and sisters]," or teachers, to a life of verbal purity. The concession is simple, a timeless bit of wisdom: "For all of us make many mistakes." ... (Job 4:17; Psalm 19:12; Proverbs 20:9; Jeremiah 17:9) ... James does not believe in sinlessness, nor does any writer in the New Testament (cf. 1 John 1:8), but he does believe that those who have the implanted word (James 1:21) can obey the royal law of love (1:25-27; 2:8-13). The royal law of love manifests itself in verbal purity ..."
McKnight, Scot The Letter of James (pp. 272-274) William B. Eerdmans Publishing Company, 2011