Mat 24:13 But he that shall endure unto the end, the same shall be saved. Mat 24:14 And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.
How can the Jews preach the gospel of the kingdom, that Matt. 24.14 is referring to, if they do not know Christ?

The only way I have ever been able to explain this is to say there is a remnant of the Jewish nation that does not believe in Christ, yet because God must save (this save does not mean born-again) a remnant, as He keeps His promise to His chosen nation whom He first revealed Himself to; such a Jewish remnant will preach the Messianic Kingdom or Political Kingdom.

The Messianic Kingdom is related to the Jews as the center of all nations, while the millennial kingdom, concurrently, is related to the overcomers whom come out of the Adamic race that were born-again, but also overcome in the redemptive design so that they can no longer be hurt by the second death (Rev. 20.6).

Those at the center of all nations receive their messianic kingdom promise, while the overcoming-saved receive rewards (v.4) of reigning as kings and priests (v.6) for 1000 years over all the nations ("ye also shall sit upon twelve thrones, judging the twelve tribes of Israel" Matt. 19.28 ); and non-overcoming saved are cast into outer darkness loss of rewards, outside the light of the reward of reigning with Christ, to be prepared for the new city.

And of course after the 1000 years, the unsaved are resurrected to great white throne to be cast into hell-fire, an eternal separation from God.