Matthew alone quotes the prophecy of Isaiah that mentions the hope of the Gentiles:

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        "Here is my servant whom I have chosen, the one I love, in whom I delight; I will put my Spirit on him, and he will proclaim justice to the nations… In his name the nations will put their hope" (Mat 12:18-21 / Isa 42:1-4).

        

This passage is important because it alters the content of the traditional Jewish expectation of the treatment of the Gentiles -- and it uses the Old Testament as its authority in doing so. It was expected that the Messiah would bring justice and judgment on a universal scale, but usually this meant retribution for the sins of the nations against Israel, and the vindication of God's people. Some Old Testament prophecies that we studied showed the foreign nations in a subservient role to Israel. But the passage that Matthew quotes from Isaiah shows that the Messiah's Name is the hope of the nations, which means He brings them good news, not punishment.

        

This section is not Jesus' own words, it is Matthew’s parenthesis, his commentary, on how Jesus' actions fulfill the role of the Messiah.