What does the Scripture say? "Abraham believed God, and it was credited to him as righteousness (Rom 4:3).

Abraham counted the stars in heaven, and God said to him, “So shall your offspring be.” And he believed that what God said would be fulfilled, and his faith was counted as righteousness. Just as he counted the stars, God counted him as righteous. It was the most vital step that he had to take in order for God’s plan and promise to be fulfilled in him. In the same way, in order for God’s word to be fulfilled in you and for all his promises to come true, you must be righteous before him.

Surely the arm of the Lord is not too short to save, nor his ear too dull to hear. But your iniquities have separated you from your God; your sins have hidden his face from you, so that he will not hear (Isa 59:1-2).

The truth is that God desires to save you more than you want him to save you, but he cannot if you are unrighteous before him. However, once this unrighteousness is removed, he can save you from all problems and sufferings, and his blessings can be yours unlimitedly.

Therefore, the promise (to be heir of the world) comes by faith, so that it may be by grace and may be guaranteed to all Abraham's offspring—not only to those who are of the law but also to those who are of the faith of Abraham. He is the father of us all (Rom 4:16).

As Abraham was counted as righteous by faith, we who believe in Christ were also counted as righteous by faith, not by works.

Yet he did not waver through unbelief regarding the promise of God, but was strengthened in his faith and gave glory to God, being fully persuaded that God had power to do what he had promised. This is why "it was credited to him as righteousness (vv. 20-22)."

“To do what he had promised” means “to fulfill what he had promised.” Abraham believed in the fulfillment of God’s word, and you followed him by believing the same way. Thus, you were counted as righteous the same way. No matter how acutely Satan brings charges against you, it is God who justified you and counted you as righteous through Christ. You can always go near to him and stand before him with boldness and confidence.

… let us draw near to God with a sincere heart in full assurance of faith, having our hearts sprinkled to cleanse us from a guilty conscience and having our bodies washed with pure water (Heb 10:22).

Yet, you should not forget that it was by the following truth that you were made righteous. Jesus said:

It is written: “And he was numbered with the transgressors”; and I tell you that this must be fulfilled in me. Yes, what is written about me is reaching its fulfillment (Luke 22:37).

Sin is spiritual, and unrighteousness is a spiritual condition—a reality in the spiritual world. Christ did not sin in this physical world, yet he was numbered (counted) as unrighteous in the spiritual world. On the other hand, we who sinned in this world were counted righteous in the spiritual world through Christ. This, too, came as the fulfillment of God’s word, and we are Abraham’s offspring, the new humanity—the believers of the fulfillment of God’s word.