The great plan of redemption (v. 31) is the great plan of the Eternal God that Amulek had mentioned just before (v. 10). While that plan was presented to all in the pre-mortal council, it was to be followed by each of us when it is our time to be on earth. However, for some that time includes the spirit world after death. President Joseph Fielding Smith has explained:
The promise is unto all who repent whether living or dead, that they shall not be deprived of the opportunity of hearing and accepting the truth. Therefore there must be a time for teaching the dead who died without the privilege of hearing and receiving the gospel when they were here on the earth. This wonderful doctrine was revealed to the Prophet Joseph, and he was given the divine authority to have the ordinances performed for the dead in the temples built for that purpose. This is a just principle filled with the spirit of mercy, love, and justice.
That every soul shall have his chance is one of the greatest principles of the gospel. It is merciful and it is just, but these Zoramites could not see it because they had rebelled against the truth and had turned to the worship of false gods and thus had placed themselves on the border where there would be no hope if they continued in their evil course. So we see that there is no conflict between Amulek’s teachings and the doctrine of the loss of salvation for the dead who turn away in this life and place themselves beyond hope of their redemption.
In the spirit world every person will have the opportunity to exercise their agency and accept or reject the great plan. Our mortal probation was designed to prepare for eternity (v. 33). To procrastinate is to postpone until tomorrow the things we should be doing today. For those who did not have a full opportunity to improve while on earth, there will be given additional time in the spirit world according to the justice of God. However, when that time has been met, darkness will prevail and there can be no labor performed (v. 33). Therefore the fallacious doctrine of death-bed repentance is not according to the plan of God.
The same spirit that possesses your body when you leave this world (v. 34) has been interpreted by some to say our spirit will be the same in the spirit world as it is when we depart this life. While that is a true principle, Amulek is speaking of the time when we are to improve our life. The gospel is preached in the spirit world “that they might be judged according to men in the flesh, but live according to God in the spirit” (1 Peter 4:6). If we live according to God, we will be growing intellectually, socially, and spiritually. As the Apostle Paul said: “If in this life only we have hope in Christ, we are of all men most miserable” (1 Corinthians 15:19).
“That same spirit which doth possess your body at the time that ye go out of this life, that same spirit will have power to possess your body in that eternal world” (Alma 34:34) may have reference to a spirit other than your own, as shown in the next verse. The Spirit of the Lord possesses you or will be withdrawn from you. If it does withdraw, you are subject to be possessed by the spirit of the devil. The Prophet Joseph taught:
Salvation is nothing more nor less than to triumph over all our enemies and put them under our feet. And when we have power to put all enemies under our feet in this world, and a knowledge to triumph over all evil spirits in the world to come, then are we saved, as in the case of Jesus, who was to reign until He had put all enemies under His feet, and the last enemy was death. [ TPJS, 297]
Thus our bodies will be possessed as determined by our righteousness or wickedness (v. 36).