Jamieson, Fausset and Brown on Mark 13:13

13. And ye shall be hated of all men for my name's sake--Matthew (Mt 24:12) adds this important intimation: "And because iniquity shall abound, the love of many"--"of the many," or "of the most," that is, of the generality of professed disciples--"shall wax cold." Sad illustrations of the effect of abounding iniquity in cooling the love even of faithful disciples we have in the Epistle of James, written about the period here referred to, and too frequently ever since.

but he that shall endure unto the end, the same shall be saved--See on Mt 10:21, 22; and compare He 10:38, 39, which is a manifest allusion to these words of Christ; also Re 2:10. Luke (Lu 21:18) adds these reassuring words: "But there shall not an hair of your heads perish." Our Lord had just said (Lu 21:16) that 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 Psa 91:1-18 and such like.