Did Israel hear the message of the Gospel?
Yes. Scripture declares that Israel did hear: "their sound went into all the earth, and their words unto the ends of the world." Paul asks whether they heard, and the answer is yes, though the same passage notes Israel did not truly know, so hearing alone did not guarantee understanding or belief.
Les teaches that Paul comes back to Israel’s situation in verse 18, asking, “But I say, have they not heard? Yes verily, their sound went into all the earth, and their words unto the ends of the world.” Paul then asks, “I say then, did not Israel know?” Les emphasizes that when Jesus came to the nation of Israel, they could have known who He was, and they should have known who He was, but the text says, “But Israel did not know.” So Israel heard the outward witness, yet did not truly know, while the present responsibility is for Gentiles to believe the Gospel revealed through Paul, the Gospel of the Grace of God.
But I say, Have they not heard? Yes verily, their sound went into all the earth, and their words unto the ends of the world.