John Calvin Commentary Romans 4:2

"For if Abraham was justified by works, he hath whereof to glory; but not toward God." — Romans 4:2 (ASV)

For if Abraham, etc. This is an incomplete argument, which may be made in this form — “If Abraham was justified by works, he might justly glory: but he had nothing for which he could glory before God; then he was not justified by works.” Thus the clause but not before God, is the minor proposition; and to this must be added the conclusion which I have stated, though it is not expressed by Paul. He calls that glorying when we pretend to have anything of our own for which a reward is supposed to be due at God’s tribunal. Since he takes this away from Abraham, who of us can claim for himself the least particle of merit?