"Must unavoidably perish"

1. Mosiah 13: 28
   28 And moreover, I say unto you, that salvation doth not come by the law alone; and were it not for the atonement, which God himself shall make for the sins and iniquities of his people, that they must unavoidably perish, notwithstanding the law of Moses.
2. Alma 34: 9
   9 For it is expedient that an atonement should be made; for according to the great plan of the Eternal God there must be an atonement made, or else all mankind must unavoidably perish; yea, all are hardened; yea, all are fallen and are lost, and must perish except it be through the atonement which it is expedient should be made.
3. Hel. 4: 25
   25 Therefore the Lord did cease to preserve them by his miraculous and matchless power, for they had fallen into a state of unbelief and awful wickedness; and they saw that the Lamanites were exceedingly more numerous than they, and except they should cleave unto the Lord their God they must unavoidably perish.