James 2:21 - Joseph Benson’s Commentary on the Old and New Testaments

Was not, &c. As if he had said, Take an instance of this in the most celebrated of all the patriarchs, our father Abraham. Was not he justified by works Did not his works manifest the truth and liveliness of his faith; when In consequence of the full persuasion he had of a divine command to do it; he offered Isaac his son upon the altar? Intending, in obedience to what he apprehended to be the will of God, actually to have slain him, and to have trusted in God to accomplish the promise of a numerous seed to descend from him, by raising him from the dead: see notes on Hebrews 11:17-19. St. Paul says Abraham was justified by faith, (Romans 4:2, &c.,) yet St. James does not contradict him. For he does not speak of the same justification. St. Paul speaks of that which Abraham received many years before Isaac was born, Genesis 15:6; St. James of that which he did not receive till he had offered up Isaac on the altar. He was justified, therefore, in St. Paul's sense; that is, accounted righteous by faith, antecedent to his works. He was justified in St. James's sense, that is, made righteous by works, subsequent to his faith: so that St. James's justification by works is the fruit of St. Paul's justification by faith.