Your question implies that you don't understand what immortality is or how it is achieved. Without receiving eternal life, we are dying our bodies cannot survive without longevity. First off it is a gift from God that is given to faithful humans' period, immorality is never granted to unbelievers, John 3:16. Another point is that the concept is Christian in form and was revealed by Jesus Christ to people as the Messiah, John 11:17-27. Immorality is one of the things revealed by Jesus Christ as a free gift. There is of course more to it, but I want you to think about it and then ask the questions that will give you more information about the Christian concept of immorality, 1 Corinthians 15:42-57.