How do beliefs about the afterlife differ between Judaism Christianity and Islam?

Answer 1

Judaism 1:

Judaism barely spends any time discussing what may or may not happen when we die, in fact, there's barely any mention of this subject in the Tanach (Jewish Bible) at all.

There are some loose theories of what might happen though:

* When we die, our souls are cleansed of any wrongdoings. This is done by our accounting of every action done in life. It's believed that this process takes no longer than 12 months but most people don't do enough bad in life to warrant it taking a full 12 months.

* Our souls return to HaShem to wait for the world to come.

* Our souls may be reincarnated into different people so that we have additional chances to work to become closer to HaShem.

* Those souls that choose to be truly evil in life, cannot survive the process of cleansing and cease to exist.

Judaism 2:

One of the central beliefs of Judaism, as codified by Rambam (Maimonides), is that the soul continues to exist and is treated in accordance with the person's actions while he/she was alive. All outstanding accounts are settled after this life. Some cases illustrate this point, since this entire world wouldn't be enough to reward a Moses or punish a Hitler.
The afterlife is detailed at length in the Talmud. A full 20 pages of Talmud (Sanhedrin 90-110) are given to this subject. The afterlife is also referred to briefly in Torah (Bible) verses such as Genesis 15:15, which states that "You (Abraham) will come to your fathers in peace and will be buried in good (ripe; full) old age." This does not mean merely to be buried with one's forefathers, since Abraham was not buried with them. Such verses are stated many times.
The prophets are more explicit with such references (such as Isaiah 26:19, Daniel 12:13).
The Tanakh does not delve into detail of the rewards of the righteous, because other religions could compete with even more poetic promises. Also because belief in the afterlife was shared by all ancient societies and needed little reiteration. See the Kli Yakar commentary to Leviticus ch. 26 for a fuller discussion.

Discussion of All Three

Judaism: In Judaism, there is no eternal delineation between good souls and evil souls as is common in Christianity and Islam. Judaism holds that the Satan is still in heaven, which further means that there is no King of the Damned or any form of Eternal Damnation. During the Afterlife period, there are different mechanisms by which the soul must come to spiritual fitness in order to be a part of the eventual resurrection of the dead. Some Kabbalists say that this comes by way of reincarnation, but the dominant opinion in Judaism is that souls must exert themselves painfully to open up new levels of holiness.

Christianity: The Christian afterlife is based in a place above us, i.e. the Spiritual Heavens. There is an initial selection where those who did not join in with Christ's saving grace are sent to Hell, a realm of fire and brimstone over which Lucifer, the Devil, reigns supreme. Those who are Believers ascend to the Pearly Gates of Heaven and sit alongside God the Father in the majesty of Heaven for eternity. What Heaven actually looks like is not terribly developed, but it is believed to be a "good place". For those that are not clearly bound for Hell or Heaven, there is a third realm called Purgatory where Christians are challenged so that they can be properly resorted later.

Islam: Islam has a conception of Paradise or Jinnah, which resembles the Garden of Eden in many respects. This Spiritual Place operates very similarly to Earth in that there are gardens, people, food, beverages, etc. It is paradise in that all of these things come without their negative side effects. Jinnah has multiple levels, each designated for those who exist on different levels of holiness. There is also discussion of the presence of virgins for the deceased, although the number of virgins differs between traditions. Those who did not believe in Islam (or Judaism or Christianity) are sent to the Hellfire which operates quite similarly to the one described in Christianity.