“He believed in the Lord, and he deemed it righteous of him” (Gen. 15:6).
Who is the “he” and who is the “him”?
Rashi and others say that because Abraham had faith, God was pleased and attributed merit to the patriarch.
Ramban thinks it was the other way round. Abraham gave credit to God as a reliable Ruler who keeps His promises, and that’s why the patriarch believed in God.
The Divine prophecy that Abraham would have progeny and destiny (verses 1-5) would certainly come to pass.
There might be difficulties along the way, but God could be depended upon.