Blessed Is The Man To Whom The Lord Will Not Impute Sin
It is commonly taught and preached amongst the "faith alone" groups (Protestant, Lutheran, Baptist etc) that as long as a person believes in Jesus, that his sins will not be imputed.
Excerpt From Justin Martyr (Ante Nicene)
“But that you may not have a pretext for saying that Christ must have been crucified, and that those who transgressed must have been among your nation, and that the matter could not have been otherwise, I said briefly by anticipation, that God, wishing men and angels to follow His will, resolved to create them free to do righteousness; possessing reason, that they may know by whom they are created, and through whom they, not existing formerly, do now exist; and with a law that they should be judged by Him, if they do anything contrary to right reason: and of ourselves we, men and angels, shall be convicted of having acted sinfully, unless we repent beforehand. But if the word of God foretells that some angels and men shall be certainly punished, it did so because it foreknew that they would be unchangeably [wicked], but not because God had created them so. So that if they repent, all who wish for it can obtain mercy from God: and the Scripture foretells that they shall be blessed, saying, ‘Blessed is the man to whom the Lord imputeth not sin;’ that is, having repented of his sins, that he may receive remission of them from God; and not as you deceive yourselves, and some others who resemble you in this, who say, that even though they be sinners, but know God, the Lord will not impute sin to them. We have as proof of this the one fall of David, which happened through his boasting, which was forgiven then when he so mourned and wept, as it is written. But if even to such a man no remission was granted before repentance, and only when this great king, and anointed one, and prophet, mourned and conducted himself so, how can the impure and utterly abandoned, if they weep not, and mourn not, and repent not, entertain the hope that the Lord will not impute to them sin? And this one fall of David, in the matter of Uriah’s wife, proves, sirs,” I said, “that the patriarchs had many wives, not to commit fornication, but that a certain dispensation and all mysteries might be accomplished by them; since, if it were allowable to take any wife, or as many wives as one chooses, and how he chooses, which the men of your nation do over all the earth, wherever they sojourn, or wherever they have been sent, taking women under the name of marriage, much more would David have been permitted to do this.”