Adam Clarke on James 2:23

The scripture was fulfilled - He believed God; this faith was never inactive, it was accounted to him for righteousness: and being justified by thus believing, his life of obedience showed that he had not received the grace of God in vain. See the notes on Gen 15:6; Rom 4:3 (note); Gal 3:6 (note); where this subject is largely explained.

The friend of God - The highest character ever given to man. As among friends every thing is in common; so God took Abraham into intimate communion with himself, and poured out upon him the choicest of his blessings: for as God can never be in want, because he possesses all things; so Abraham his friend could never be destitute, because God was his friend.