But the Scripture - The Old Testament (see the note at John 5:39), containing the Law of Moses.
Hath concluded all under sin - Has “shut up” (συνέκλεισεν sunekleisen) all under the condemnation of sin; that is, has declared all people, no matter what their rank and external character, to be sinners. Of course, they cannot be justified by that law which declares them to be guilty, and which condemns them, any more than the Law of the land will acquit a murderer, and pronounce him innocent, at the same time that it holds him to be guilty. In regard to the meaning of the expression used here; see the note at Romans 11:32; compare Romans 3:9, Romans 3:19. “That the promise by faith of Jesus Christ, etc.” That the promise referred to in the transaction with Abraham, the promise of justification and life by faith in the Messiah. Here we see one design of the Law. It was to show that they could not be justified by their own works, to hedge up their way in regard to justification by their own righteousness, and to show them their need of a better righteousness. The Law accomplishes the same end now. It shows people that they are guilty; and it does it in order that they may be brought under the influence of the pure system of the gospel, and become interested in the promises which are connected with eternal salvation.