Our life in this world is not our complete life. We lived before and we will live after. Where were we before we were born? In a spiritual world. The Ariz”l – Rabbi Yithak Luria – says that most people nowadays are reincarnated souls.
A person’s soul may have been in another body in the past. I know a psychologist that is versed in hypnosis. He told me stories of people he hypnotized – that he brought back to a past life. The soul remembers. The body may not.
Knowing that fact – what do we do now? The Torah says – now we came here to repair past misdeeds or to accomplish a particular purpose. We can find our purpose by learning Torah from a competent Orthodox Rabbi. (see torahanytime.com)
Those – who did achieve their purpose go on to another heavenly world. When a person in this world has a marriage – the souls of family members from the next world come to attend.
The souls of relatives also come to greet a person on the day they depart from the world. Thus the French term – Au Revoir (See You Again) is more applicable to say to a departed soul than a final goodbye.