Acts 28:25

And when they agreed not among themselves, they departed after that Paul had spoken one word.

As Bruce said, "It would be a great, mistake to suppose the exposition took the form of a monologue. The debate must have been keen and impassioned."[27] There is no need, then, to view the "one word" of this verse as being composed of Paul's quotation from Isaiah which immediately follows, which is, in fact, not "one word" in any sense. What, therefore, is that "one word" which broke up this meeting? Luke had already related how the temple mob heard Paul patiently until a single word, the word "Gentiles" (Acts 22:21,22), the strong likelihood being that it was exactly that same word which signaled the end of the meeting here. Luke did not spell it out again; but Paul's appeal to the prophecy of Isaiah as foretelling their rejection strongly infers this.

Well spake the Holy Spirit through Isaiah the prophet unto your fathers, saying, Go thou unto this people, and say, By hearing ye shall hear, and shall in no wise understand; And seeing ye shall see, and shall in no wise perceive: For this people's heart is waxed gross, And their ears are dull of hearing, And their eyes they have closed; Lest haply they should perceive with their eyes, And hear with their ears, And understand with their heart, And should turn again, And I should heal them.

This is Isaiah 6:9,10; and although spoken "through" Isaiah, it is clearly presented here as the word of the Holy Spirit.

This same passage was applied to Israel by Christ, as affirmed in all four gospels (Matthew 13:15,15; Mark 4:12; Luke 8:10; and John 12:37-41). The significance of its being repeated here lies in the fact that the same blindness that closed the hearts of Israel to the Christ was still operative in closing their hearts against the gospel. Paul had already written in Romans a detailed prophecy of the hardening of Israel, proving by many Old Testament passages that their rejection had been foreknown of God from of old. Paul already had the most extensive knowledge of that self-induced blindness to the truth on the part of the chosen people, but he had no doubt hoped until now that some change in the pattern might come to pass in Rome. The interview just concluded blasted any such hopes.

Up until this time, Paul had ever gone "to the Jew first," but in the light of this final rejection in the heart of civilization, he promptly announced in the next verse the termination of that phase of Christianity.