Genesis 15:6 (NKJV)
And he believed in the Lord, and He accounted it to him for righteousness.
I looked at many translations of this verse and found many renderings of the word for accounted. I found counted, reckoned, credited, accepted, considered worthy, was pleased with, and declared.
God did not find some valuable asset in Abram and then recognize it. It is more like a transaction where someone deposits assets into your account.
Abram said, “I don’t see it, but I believe it.” God then said, “Righteous!”
That Hebrew word for believe is "aman". It means to be trustworthy, true, confirmed, established, verified, certain, reliable. What does that word remind you of? When we say our prayers, Amen or "so be it". Jesus used that word when he said, truly truly, verily verily, most assuredly. In the Hebrew language, the way you make a superlative is to double the word or even triple the word (like Holy, Holy, Holy is the Lord God of hosts).
So Abram hears God’s word, then he believes. This kind of belief affects behavior. Abraham will eventually act this belief out in obedience to God.
Now note when Abram was counted righteous. Not when he obeyed God about leaving Ur of the Chaldees but when he believed. What was it that Abram believed in? God had just promised him that he would give him a son and that his seed (descendants) would be greater than the stars in the heavens.
So what Abram believed that was accounted to him for righteousness was the promise regarding the Seed. And who is that Seed?
Galatians 3:16 (NKJV)
Now to Abraham and his Seed were the promises made. He does not say, “And to seeds,” as of many, but as of one, “And to your Seed,” who is Christ.
It is not mere faith that saves but faith in Jesus Christ!
Genesis 15:7-8 (NKJV)
Then He said to him, “I am the Lord, who brought you out of Ur of the Chaldeans, to give you this land to inherit it.” And he said, “Lord God, how shall I know that I will inherit it”
There it is, the difference. The world says show me and I’ll believe it. Abraham said I believe it, now show me.