God simply accounts righteousness, the righteousness of Christ, where righteousness does not in reality exist. When we are justified, He looks upon us as though we were sinless like His Son. That is awesome! Do we deserve that? Have we earned it? It is incredible that He should deal with us as though we were righteous and without sin!
In "account," we are obviously dealing with an accounting term. The picture is as if a person were looking at a ledger, and every figure is in the debit column. He is hopelessly in debt; he cannot figure out how to bring things into balance. He could never earn enough because His income is not great enough. He has no real assets. Nothing can balance the account. In his despair, he cries out to God. Then he looks at his ledger, and suddenly a figure appears on the credit side that completely balances the account. The debt is gone!
Justification is not something that we can earn. God, for His own reasons, determines to favor us with it. As Paul puts it in Ephesians 2:8-9, it is by grace through faith, not of works.
John W. Ritenbaugh
Grace Upon Grace