It interesting to find out that the Book of the Dead also called the Pyramid Text which dates back to 1500 BCE is most likely where Christianity gets its origins. The Egyptians believed that when one died his spirit or one aspect of it would go to heaven then return to the resurrected body. The body was mummified to prepare it for the resurrection and all organs taken out of it except the heart.
After the body was resurrected the person would travel through the Under-World having to meet and pass judgment by 42 gods. When speaking to each one of these gods the person would speak a Negative Confession, meaning he would state that he did not do a certain thing like "He did not murder anyone". These Negative Confessions is most likely where most of the Ten Commandment's came from for all but the ones about worshipping only one god etc. are found in these Negative Confessions.
After the person successfully passed these judgments there was one final judgment left, judging of the heart. In the bible it talks about ones heart condition and finally in the book of Revelations one is judged by his heart condition, and this is where this idea comes from. When the Egyptian enter the room his heart would be weighed against a feather. If his heart was impure he would die a final second death for all eternity,(Sound familiar) by a ferocious beast.
If the persons heart was pure he would pass the test and move on to paradise and live for eternity with other loved ones in a placed called The Field of Reeds also called Field of Offerings.
In other versions of the Book of the Dead, the Kings (pharaohs) would travel through the Under-World at night when the sun, (Ra) was down or dead in their beliefs and go through a set of trials. Some trials had to do with a lake of fire and also surviving being attacked by a giant snake named Apophis god of the Under-World, he also represented Chaos
I'm not 100% sure on this yet but from what I have read it looks as the the kings would not just go and live forever in the Field of Reeds but instead travel to heaven merge with Ra and lived in the heavens forever among the stars.
Its also worth mentioning that the Egyptians were obsessed with getting their hands on a Book of the Dead, because with out this book one would not have the spells and incantations needed to get through the Under-World facing monsters and tests etc. And of course in order to get one of these Books Of the Dead and any other trinket one may need, the person would have to spend a lot of money and pay yeah you guessed it, the Priests for these items. Its unfortunate that just like today many Egyptians would spend most of their lives obsessing over this future event and trying to prepare as well as getting the money needed so they could have a successful journey to Paradise.