For what does the Scripture say? “Abraham believed God, and it was counted to him as righteousness.” (ESV)
We love to give ourselves credit, even when we do not deserve it. When it comes to our relationship with God there are many people who think that their own works have purchased a right standing with God. You can be sure, they are giving themselves credit that they do not deserve. When it comes to faith it comes down to God's credit, not ours.
Paul says that Abraham believed God, and God counted Abraham's faith, or belief, as righteousness. This word "counted" is a legal term. It can be translated as "credited." It is as if your righteousness is a bank account. On your own you are bankrupt. God graciously looks at your account and credits it with his righteousness. You are wealthy beyond your wildest dreams.
Paul is making a case that he wants the Jews to understand. They insisted that their righteousness was achieved by keeping the Law. The sad reality was that all the works they could possibly do would never amount to anything to their "righteousness account." God is the one who imparts righteousness to our account. He gets the credit.
Abraham's faith was the avenue of receiving righteousness, not his works. Abraham's works were substantial by human standards, but not by God's standards. The same is true for us. Faith is necessary, but even faith itself is a gift of God as Paul made clear to the church at Ephesus in Ephesians 2:8. We are saved by grace, through faith, and this is not of ourselves.
What's in your "righteousness account?" If you are hoping that your works are purchasing righteousness for you, you are bankrupt. Place your faith in God, and rely on his crediting your account.