Adam Clarke on James 2:25

Rahab the harlot - See the notes on Jos 2:1, etc., and Heb 11:31 (note), etc. Rahab had the approbation due to genuine faith, which she actually possessed, and gave the fullest proof that she did so by her conduct. As justification signifies, not only the pardon of sin, but receiving the Divine approbation, James seems to use the word in this latter sense. God approved of them, because of their obedience to his will; and he approves of no man who is not obedient.