Jamieson, Fausset & Brown

Verily I say unto you, All these things shall come upon this generation--As it was only in the last generation of them that "the iniquity of the Amorites was full" (Gen 15:16), and then the abominations of ages were at once completely and awfully avenged, so the iniquity of Israel was allowed to accumulate from age to age till in that generation it came to the full, and the whole collected vengeance of heaven broke at once over its devoted head. In the first French Revolution the same awful principle was exemplified, and Christendom has not done with it yet. Lamentation over Jerusalem and Farewell to the Temple (Mat 23:37-39).