"Now it was not written for his sake alone that [righteousness] was imputed to him, but also for us. It shall be imputed to us who believe in Him who raised up Jesus our Lord from the dead, who was delivered up because of our justification." - Romans 4:23-25
Paul spends the majority of chapters two and three of Romans painting a picture of man's sinful nature. In chapter two he declares that we are "inexcusable" when we judge because we have all done the same things and in chapter three he goes on to declare that all have sinned and all have "come short of the glory of God" (v.23). But then at the end of chapter two his tone begins to change. He starts talking about the righteousness of God being revealed and in chapter four he goes back to some very familiar characters in Jewish history to prove a point. Paul specifically focuses on Abraham. He reminds his readers of the scripture which declares that Abraham's faith "was accounted to him for righteousness" (4:22). This is quoting Genesis 15:6 which states: "Abram believed the Lord, and he credited it to him as righteousness." (NIV)
Paul tells his readers that Genesis 15:6 wasn't just declaring Abram's righteousness but was setting forth a standard for us. Abram was an example. He achieved righteousness through believing God and we can follow that same example. Of course now we have something very specific to believe in; the death and resurrection of our Lord Jesus Christ. When we believe and accept this fact the Word said that righteousness is imputed to us. If you look up the definition of the word 'imputed' you will find that it means "made a characteristic". In other words, our belief makes righteousness so much a part of us that it becomes one of our characteristics! We often describe people by there characteristics, for example someone might describe me as: light brown hair, green eyes, broad shoulders, about six feet. According to Paul, because of my belief in Christ, someone could just as accurately throw "righteous" in there as a part of the description!
Let's remember today the righteousness that has been imputed to us. Stop calling yourself a sinner, stop declaring your weaknesses or shortcomings over your self. You are righteous! It is one of your characteristics.