Since men and women cannot be received on the basis of their natural goodness, which is inadequate and unfair, God receives them on the basis of their faith. The faith they show is counted by Him as righteousness. This is the great doctrine of justification by faith and explains why it is impossible to come to God faithless, and why those who come must believe. In order to show how the great principle operates the Apostle Paul takes the case of one man, Abraham. Abraham received certain promises from God which, at the time they were spoken, appeared, humanly speaking, to be impossible of fulfilment. But Abraham had faith in the promises in spite of adverse appearances and God counted this for righteousness:
"He staggered not at the promise of God through unbelief; but was strong in faith, giving glory to God; and being fully persuaded that, what he had promised, he was able also to perform. And therefore it was imputed to him for righteousness. Now it was not written for his sake alone, that it was imputed to him; but for us also, to whom it shall be imputed, if we believe on him that raised up Jesus our Lord from the dead; who was delivered for our offences, and was raised again for our justification" (Romans 4:20-25).
Paul insists that the principles which operated in the case of Abraham are true for every man who will come to God for salvation."
One Bible, Many Churches - Does it Matter What We Believe?