Sin made him mortal. Everyone thinks about and fears death, for obviously different reasons, but this is the truth. Let us see, though, what death is, and then see if we should fear death or life or even ourselves. When people think of death they put in their minds catastrophe and the end. This is not how things are.
Death is a stage and a starting point.
It is neither the end, nor a catastrophe. It is a change of circumstances. It is birth. Just as the embryo grows in the womb of its mother for nine months and is then born, so too man in his earthly life works for his salvation, and then he dies. In other words, he is born into eternity.