Alma clarifies that the temporal death he spoke of earlier is the same death that came upon Adam and all of humankind. Because of Adam, we all die a temporal death.
Next he provides a context for earth life. It is the “space granted unto man in which he might repent.” Repentance is how we prepare ourselves “to meet God,” a state that will come after the resurrection and, by implication, after the judgment.
Alma suggests that it would have been possible for Yahweh to cut off humankind at the point of the fall. If the end had come then, all would be condemned, since all were subject to death. By Yahweh’s mercy, mortality continues, allowing us time to prepare ourselves for the “endless state” that comes next.