Matthew 24:34

Verily I say unto you, this generation shall not pass
Not the generation of men in general; as if the sense was, that mankind should not cease, until the accomplishment of these things; nor the generation, or people of the Jews, who should continue to be a people, until all were fulfilled; nor the generation of Christians; as if the meaning was, that there should be always a set of Christians, or believers in Christ in the world, until all these events came to pass; but it respects that present age, or generation of men then living in it; and the sense is, that all the men of that age should not die, but some should live till all these things were fulfilled;
see ( Matthew 16:28 ) as many did, and as there is reason to believe they might, and must, since all these things had their accomplishment, in and about forty years after this: and certain it is, that John, one of the disciples of Christ, outlived the time by many years; and, as Dr. Lightfoot observes, many of the Jewish doctors now living, when Christ spoke these words, lived until the city was destroyed; as Rabban Simeon, who perished with it, R. Jochanan ben Zaccai, who outlived it, R. Zadoch, R. Ishmael, and others: this is a full and clear proof, that not anything that is said before, relates to the second coming of Christ, the day of judgment, and end of the world; but that all belong to the coming of the son of man, in the destruction of Jerusalem, and to the end of the Jewish state.