Paul raises the obvious excuse so he can answer it. If faith comes by hearing, someone might say that people who did not believe simply never heard. Barnes introduces Paul's words this way: "But to this objection, I, the apostle, reply." Gill notes that "But I say" "is a phrase frequently used by the Jewish doctors in disputation," when raising or answering objections. Paul asks the question to show that the excuse does not hold.

Paul answers at once: "Yes verily, their sound went into all the earth, and their words unto the ends of the world" (Romans 10:18). The message had gone out widely. He then asks a second question, "Did not Israel know?" (Romans 10:19), and shows from Moses and Isaiah that Israel had been told the Gentiles would be brought in (Romans 10:19-20). The chapter ends with God saying, "All day long I have stretched forth my hands unto a disobedient and gainsaying people" (Romans 10:21).

Paul borrows the words of Psalm 19:4, where the heavens and the firmament declare God's glory to every land (Psalm 19:1-4). Barnes explains that "the apostle does not affirm that David had reference to the gospel in them, but he uses them to express his own meaning." The KJV of Psalm 19:4 reads "Their line is gone out"; Barnes notes that the Hebrew has "their line," while the Septuagint, the ancient Greek translation of the Old Testament, reads "their voice," as Paul does. Gill mentions some who suspect the Septuagint used a Hebrew copy reading "their voice," but he does not accept that; he explains that the Hebrew word for "line" can also carry the sense of a sound. Barnes adds that "During the time which had elapsed after the ascension of Christ, the gospel had been preached extensively in all the known nations."

God does not leave Himself without a witness. The same psalm that says creation speaks to every land is the one Paul uses to say the gospel had spread far and wide (Psalm 19:1-4; Romans 10:18). The God who made the heavens to declare His glory also sent messengers to declare His Son.

Matthew Henry stresses that the gospel went out with "not only a confused sound, but their words," that is, a clear message people could understand. The problem Paul faces is not that God was silent. It is that some who heard did not believe (Romans 10:16, 21).