Alma 34:6 - 34:10
Alma 34: 6 And ye also beheld that my brother has proved unto you, in many instances, that the word is in Christ unto salvation.
Amulek reiterates that the word referenced by Alma is Christ and His message of salvation to all mankind.
Alma 34: 7 My brother has called upon the words of Zenos, that redemption cometh through the Son of God, and also upon the words of Zenock; and also he has appealed unto Moses, to prove that these things are true.
And that Alma has quoted the prophets Zenos and Zenock to prove his point.
Alma 34: 8 And now, behold, I will testify unto you of myself that these things are true. Behold, I say unto you, that I do know that Christ shall come among the children of men, to take upon him the transgressions of his people, and that he shall atone for the sins of the world; for the Lord God hath spoken it.
Amulek adds his personal testimony to Alma’s. He testifies that Christ will come to earth and be like all men as mortals. He will suffer the same maladies as every person and he will die to atone for everyman’s sins. This plan was put in place by the Father.
Alma 34: 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.
He knows that the Christ perform the great atonement and bring salvation to all men. If the Father had not set up the plan of salvation, the people would have to had suffered for their own sins and be denied entrance to heaven.
Alma 34: 10 For it is expedient that there should be a great and last sacrifice; yea, not a sacrifice of man, neither of beast, neither of any manner of fowl; for it shall not be a human sacrifice; but it must be an infinite and eternal sacrifice.
It is necessary that this sacrifice be performed. The sacrifice will not be of an animal like a sheep or bird and it will not be a human sacrifice that has no effect as practiced by the world, but it will be kind of sacrifice that will have eternal effects.