First, let's look into the OT. Under the OT, the law, a man could be righteous before God by walking in all the commandments and ordinances of the law, however, it was self righteousness. A man could be blameless under the law, but not sinless.
Deuteronomy 6:25 And it shall be our righteousness, if we observe to do all these commandments before the Lord our God, as he hath commanded us.
2 Samuel 22:21 The Lord rewarded me according to my righteousness: according to the cleanness of my hands hath he recompensed me.
Luke 1:5 There was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth. 6 And they were both righteous before God, walking in all the commandments and ordinances of the Lord blameless.
Under the law, sins could be forgiven but not cleared. Sins would be covered, but not washed away.
Leviticus 19:21 And he shall bring his trespass offering unto the Lord, unto the door of the tabernacle of the congregation, even a ram for a trespass offering. 22 And the priest shall make an atonement for him with the ram of the trespass offering before the Lord for his sin which he hath done: and the sin which he hath done shall be forgiven him.
Exodus 34:7 Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear the guilty; visiting the iniquity of the fathers upon the children, and upon the children's children, unto the third and to the fourth generation.
Deuteronomy 6:25 And it shall be our righteousness, if we observe to do all these commandments before the Lord our God, as he hath commanded us.
2 Samuel 22:21 The Lord rewarded me according to my righteousness: according to the cleanness of my hands hath he recompensed me.
Luke 1:5 There was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth. 6 And they were both righteous before God, walking in all the commandments and ordinances of the Lord blameless.
Under the law, sins could be forgiven but not cleared. Sins would be covered, but not washed away.
Leviticus 19:21 And he shall bring his trespass offering unto the Lord, unto the door of the tabernacle of the congregation, even a ram for a trespass offering. 22 And the priest shall make an atonement for him with the ram of the trespass offering before the Lord for his sin which he hath done: and the sin which he hath done shall be forgiven him.
Exodus 34:7 Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear the guilty; visiting the iniquity of the fathers upon the children, and upon the children's children, unto the third and to the fourth generation.