So faith comes by hearing, and hearing by the word of God.
17. Faith then is by hearing, etc. We see by this conclusion what Paul had in view by the gradation which he formed; it was to show, that wherever faith is, God has there already given an evidence of his election; and then, that he, by pouring his blessing on the ministration of the gospel, to illuminate the minds of men by faith, and thereby...
The first words express the design of the apostle through these verses, that there is no difference between Jews and Gentiles, but they stand upon the same level in point of acceptance with God. In Jesus Christ there is neither Greek nor Jews, Col 3:11.
Commenting on Romans 10:12-21
So then faith [cometh] by hearing, and hearing by the word of God. (11) A conclusion of the former discussion: we must ascend from faith to our calling, for by our calling we came to the testimony of our election. (m) By God's commandment.