Alma admits he is not sure whether or not all of the people who died before the resurrection of Jesus Christ will be resurrected before any of the people who died after the time of Christ. (Alma 40:18-21.) However, he says, "I give it as my opinion, that the souls and the bodies are reunited, of the righteous, at the resurrection of Christ." (Alma 40:20.) Alma is correct, of course, in this assumption. Other prophets in the Book of Mormon make it clear that the righteous who have died will be resurrected at the time of the resurrection of the Savior. For example, Abinadi prophesied as follows:
And now, the resurrection of all the prophets, and all those that have believed in their words, or all those that have kept the commandments of God, shall come forth in the first resurrection; therefore, they are the first resurrection.They are raised to dwell with God who has redeemed them; thus they have eternal life through Christ, who has broken the bands of death.
And these are those who have part in the first resurrection; and these are they that have died before Christ came, in their ignorance, not having salvation declared unto them. And thus the Lord bringeth about the restoration of these; and they have a part in the first resurrection, or have eternal life, being redeemed by the Lord.
And little children also have eternal life.
But behold, and fear, and tremble before God, for ye ought to tremble; for the Lord redeemeth none such that rebel against him and die in their sins; yea, even all those that have perished in their sins ever since the world began, that have wilfully rebelled against God, that have known the commandments of God, and would not keep them; these are they that have no part in the first resurrection. (Mosiah 15:22-26.)
Thus Abinadi makes it very clear that the wicked will have no part in the first resurrection; the wicked, no matter when they lived, will have to wait until the final resurrection. The term "first resurrection" is used in the scriptures as a synonym for "the resurrection of the just." Thus, if one comes forth the first opportunity he has to be resurrected after he dies, he comes forth in the morning of his first resurrection.