Romans 10:18 KJV
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.
John Gill writes of this; "The Jews heard the Gospel in the times of Isaiah, and other prophets, though they disbelieved the report of it; they heard it from John the Baptist, and were pleased with his ministry for a while; yea, they heard Christ himself preach it, who spake as never man did, with power and authority, as the Scribes did not, and wondered at his gracious words; they heard the apostles of Christ, who for some time were limited in their ministry to them only, and after their commission was enlarged, were ordered to preach first to them; so that they could not say they had not heard it, and they were left entirely inexcusable. The Gentiles also had heard it; the apostles were bid to go into all the world, and preach the Gospel to every creature; and at a proper opportunity, they did as the Lord commanded them, and the Gentiles heard the Gospel with joy and pleasure; multitudes were converted everywhere, and churches raised through their ministry, according to the will of God…"
I would add that this leaves all who have gone before without excuse and that it offers no excuse for us to relax in preaching the same gospel to those coming after us.