At the end of Romans 10 and going into Romans 11, there is this idea that a person can at the same time hear the Gospel and not hear the Gospel. That is, God and his Gospel can be rightly perceived on the one hand and yet totally missed on the other. In other words, evangelism is as much based upon the work of God as it is upon the glorious commission of the church outlined in vv. 10:14, 15, namely sending out preachers, preachers preaching the Gospel, persons hearing it, believing it, and then calling upon the Lord. The reason that Paul brings up this point is because of the subject of his present discourse, namely “They have not all obeyed the Gospel” (v. 10:16). Israel has heard more than any other people of the Messiah, of God’s redemption and patience and lovingkindness, and yet they have not believed. For this reason, the apostle writes, “So faith comes from hearing, but hearing comes by the word of Christ. In other words, faith never comes about apart from the hearing of the preaching of the Gospel, but genuine hearing, hearing as a living man instead of as a dead man, comes from the word of Christ. For it is the Spirit of Christ who speaks life to soul and causes him to be born again (cf. 1Pet. 1:3) and to believe in his heart that Jesus Christ is Lord and from the abundance of his heart to confess that truth with his mouth.
Paul then writes, “But I ask, have [the Israelites] not heard? Indeed they have, for ‘Their voice has gone out to all the earth, and their words to the ends of the world’” (v. 10:18). Paul in v. 10:18 seems to take a leap back to v. 1:18, etc. and declares that the Israelites, like the rest of the world, have “clearly perceived [the divine nature and eternal power of God and thereby the Gospel] ever since the creation of the world in the things that have been made, so they are without excuse” (v. 1:20). This is his point, for this is the point of Psalm 19, which he quotes here in its context:
The heavens declare the glory of God,
….And the sky above proclaims his handiwork.
Day to day pours out speech,
….And night to night reveals knowledge.
[Yet] there is no speech,
….Nor are there words,
….Whose voice is not heard.
Their voice goes out through all the earth,
….And their words to the end of the world (Ps. 19:1-4).
Therefore, the apostle demonstrates that the Israelites have indeed heard the testimony of God as the rest of the world has–through the testimony of his creation.
Side Note: The psalmist, like the apostle, rightly understood that the testimony of the creation is lacking to bring men to a right and salvific knowledge of God, therefore he writes later in the psalm:
The law of the Lord is perfect,
….reviving the soul;
The testimony of the Lord is sure,
….making wise the simple;
The precepts of the Lord are right,
….rejoicing the heart;
The commandment of the Lord is pure,
….enlightening the eyes;
The fear of the Lord is clean,
The rules of the Lord are true,
….and righteous altogether,
More to be desired are they than gold,
….even much fine gold;
Sweeter also than honey
….and drippings of the honeycomb (Ps. 19:7-10).