Immortality does not beget wisdom.
Only mortality begets maturity.
There are people in this world who have had enough adventures for several lifetimes. They are the closest conception we can have of immortals. Yet some of these people are hopelessly immature. After all, whenever life became difficult for them, they changed to a new path and by luck the new one was always rich and fruitful. Life came so easily that they took more than one helping.
Unfortunately, maturity only comes from the threat of mortality. Success only comes from the threat of failure. Without pressure, we would not plan, utilize wisdom, or exercise care. We realize that we have only a very short time to make an achievement, to prove that our existence was worthwhile, and so we strive harder. An immortal can never conceive of such effort.
It would be good if our religious traditions provided us with a foolproof way through life. After all, we live somewhat haphazardly : Our lives are a tapestry woven of both mistakes and successes. Religion doesn’t always provide us with a meaningful pattern. We must make our decisions the best that we can, and as we mature, we can see our way better.
We are motivated by death. We are frightened by failure. We have to make our peace with this mysterious, sometimes hostile world. An immortal does not need to cope with any of this. But we mortals must, and we must strive to make a good showing for ourselves.