The apostle Paul tells us, “Blessed is the one to whom the Lord will not impute sin” (Rom. 4:8).
I think we all would agree such a person is blessed! The question is, who is that person?
I love the answer given by Justin Martyr in AD 155 or so:
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], bot not because God created them that way. If they repent, all who wish for it can obtain mercy form God, and the Scripture foretells that they will be blessed, saying, “Blessed is the man to whom the Lord will not impute sin.
This means a person may receive remission of God only if they repent of their sins. It is not as you [Jews] deceive yourselves [into thinking]—and some others who resemble you in this— saying that even though they are sinners, as long as they know God, the Lord will not impute sin to them. THe proof of this is the one fall of David … which was forgiven when he he mourned and wept in the way that it is written. So if even to a man like this, no remission was granted before repentence, and only when this great king, anointed one (Gr. christos), and prophet mourned and conducted himself in this way, how can the impure and utterly abandoned, if they fail to weep, mourn, and repent, entertain the hope that the Lord will not impute sin to them? (Dialogue with Trypho 141)