So faith comes from hearing, and hearing through the word of Christ.
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 comes by hearing,.... That is, by preaching; for the word hearing is used in the same sense as in the preceding verse; and designs the report of the Gospel, or the preaching of the word, which is the means God makes use of, to convey faith into the hearts of his people; for preachers are ministers, or instruments, by whom others believe...