Romans 10:18

But I say, Did they not hear? Yea, verily, Their sound went out into all the earth, And their words unto the ends of the world.

Paul's use of the word "hear" in this place contrasts sharply with "hearken" in Romans 10:16, where obedience is meant, hence the necessity to distinguish between them. If the KJV had been followed in Romans 10:16, there could have been no confusion.

But I say, Did they not hear? Yea, verily ... Paul had just said in Romans 10:16, "They did not all hearken," but this is not a contradiction. He meant there that they had not all obeyed, and here the meaning is that they certainly had heard.

Here we have another instance of Paul's using an Old Testament text out of context. Psalms 19:4 speaks of the universal knowledge of God through the revelation of nature; but here Paul applied the words to the worldwide preaching of the gospel. As Murray noted:

Since the gospel proclamation is now to all without distinction, it is proper to see the parallel between the universality of general revelation and the universalism of the gospel. The former is the pattern now followed in the sounding forth of the gospel to the uttermost parts of the earth. The application which Paul makes of Psalms 19:4 can thus be seen to be eloquent, not only of this parallel, but also of that which is implicit in the parallel, namely, the widespread diffusion of the gospel of grace.[17]

The ends of the earth ... translates a Greek expression which means literally, "the inhabited earth," as seen in the English Revised Version (1885) margin.