Charles Ellicott Commentary Genesis 15:6

"And he believed in Jehovah; and he reckoned it to him for righteousness." — Genesis 15:6 (ASV)

He believed in the Lord (in Jehovah) — We have here the germ of the doctrine of free justification.

Abram was both a holy man and one who proved his faith by his works. Nevertheless, the inspired narrator inserts this reflection, not after the history of the offering of Isaac, but in the account of this vision.

In this vision, all that Abram did was to believe, and on account of that belief, he was accounted righteous before God.

For the definite conclusions St. Paul deduced from this verse, see Romans 4:0.

The quotation there is from the Septuagint, and gives the general sense, but the correct rendering of the Hebrew is that given in our version.