What does Gen.15:6 mean when it says, "Abram believed the LORD and he credited it to him as righteousness?"
This is a very good and important question, so I will divide my answer into two parts. First, I will address Abram’s faith, then, I will discuss the result of his faith.
Part One: The Lord spoke to Abram using a powerful teaching tool, the night sky full of twinkling stars. “Look up at the stars,” God said to him, “and count them, if you are able.” Of course, Abram was not able to count all of the stars and that was the whole point! Then the Lord said that Abram’s offspring would be as numerous and uncountable as these stars.
We know that Abram was not a spring chicken when the Lord made this promise. Abram was in his late 70s (Gen. 12:4). He was 99 years old, when God made a covenant with him and renamed him Abraham (Gen. 17:9). The Lord often operates in ways that are beyond our understanding and with timing that seems strange to us. But faced with a seemingly impossible situation, the Bible says, “Abram believed the LORD.”
Biblical faith is not merely the acknowledgment of facts about the Lord, but trust and reliance on Him based on His Word. This text reminds us also that the Lord still desires that men and women in their 70s, 80s, 90s, and 100s trust in Him. Yes, no matter our age, we still have lessons of faith and trust to learn in the school of God. We are never too old to trust the Lord!
Part Two: In Abram’s time and still today, the Lord responds to our faith in Him. The Lord is pleased when we trust Him. Faith in the Lord has outcomes and results. The result of Abram’s trust was that the Lord reckoned it to him as righteousness. To reckon means to impute or to put on another person’s account. In other words, in response to Abram’s faith, the Lord declared that Abram was now righteous and justified in His sight. This is one of the great and wonderful truths of the Bible! Through faith in Christ, God credits us, too, with righteousness. We become the righteousness of God in Christ, being all that God requires us to be. What a glorious outcome of trust (Rom. 5:1–2).