The Christian Religion gets its roots from Judaism as the old testament of the bible is originally Jewish and is called the Tanakh
The Christian religion also gets its belief in the afterlife from Judaism
Each living creation is partly a Neshamah.
Being a Neshamah as a core part of what we are preserves us into the afterlife and it can be compared with the english word “Soul” which is related to the word “Sheol” which is a Jewish word for a place of souls that have left their flesh.
While a soul is a healthy image of the person in ethereal form, a Neshamah is connected to the soul and makes it immortal.
Thereby the soul is immortal due to the Neshamah which itself is immortal.