What is Heaven?:
In religions in the West, heaven was originally simply where God dwelled; eventually it came to be the place where the souls of good people went after death in order to be rewarded. Early biblical texts describe heaven in concrete terms an arching vault supported by pillars at the ends of the earth. Later the concept became more transcendent, but nowhere in the Old Testament is heaven described as a reward for good people.
Heaven or Heavens?:
The Hebrew word translated into English as heaven is samayim, but this is not a singular noun. Instead, it is a plural word and would best be translated as heavens, something which does occasionally appear in some translations. The Greek is also sometimes, but not consistently, rendered in the plural. Traditional theology treats heaven as a single place or existence, but the text makes it clear that we should instead speak of multiple heavens. What impact would this have for theology?
Heaven & Hell:
Heaven is normally contrasted with hell, believed to be a place of punishment for the souls of those who sinned during their lives. No such distinction existed for the ancient Hebrews, who believed that all souls would end up in Sheol a belief very similar to that of the ancient Greeks. This changed after the exile as Jews began to expect that God would reward those who were persecuted for their faith, a belief that was carried over into Christianity.
Heaven in the New Testament:
The literalness of heaven in the New Testament is open to question. The idea is expressed at times that Christians already sit with Christ in heaven and that God is omnipresent. Revelations discusses heaven more than any other New Testament text, describing it with vivid images as part of how the world will end. Most popular images of heaven are derived from this apocalyptic text.
War in Heaven:
Mormons believe that, prior to the existence of life on earth, there was a War in Heaven. Under the leadership of Satan, one-third of the angels rebelled against God; as a result of this, they were not able to later come to earth and have a mortal body.