luke 21:18 But there shall not an hair of your head perish. - Free Bible Online

      18. not a hair . . . perish--He had just said (Lu 21:16) they should be put to death; showing that this precious promise is far above immunity from mere bodily harm, and furnishing a key to the right interpretation of the ninety-first Psalm, and such like. Matthew adds the following (Mt 24:12): "And because iniquity shall abound, the love of many," the many or, the most--the generality of professed disciples--"shall wax cold." But he that endureth to the end shall be saved. Sad illustrations of the effect of abounding iniquity in cooling the love of faithful disciples we have in the Epistle of James, written about this period referred to, and too frequently ever since (Heb 10:38, 39; Re 2:10). "And this gospel of the kingdom shall be preached in all the world for a witness, and then shall the end come" (Mt 24:14). God never sends judgment without previous warning; and there can be no doubt that the Jews, already dispersed over most known countries, had nearly all heard the Gospel "as a witness," before the end of the Jewish state. The same principle was repeated and will repeat itself to the end.

JFB.