reincarnation
The theory that something of a person survives their physical death and is born again in a new body on this earth, often as part of a continual process.
EXAMPLE 1: Some people think the Son of David believed in reincarnation, while others consider the phrase "born again" to mean accepting a new, dogmatic lifestyle in the hopes (or with the promise) of changing their ways eternally for the better.

EXAMPLE 2: The Cathars were a group of heretical Christians that believed in reincarnation, but the Catholic Church convinced everyone the Cathars were wrong.

EXAMPLE 3: Buddhists believe in reincarnation of humans and animals, and that animals should be respected because they might have been or will become humans.