Mohammed gave his followers an account of what would happen at the end of the world. This day would not arrive until the whole world was conquered by Islam. Once this happens the remaining dhimmis will be murdered by the Muslims. The Jews will hide behind rocks and trees.
The rocks and trees will then grow mouths and call out to the Muslims to kill the Jews hiding behind them. Until this day happens, Muslims believe that when they die, they will lie in the grave still awake and aware. There they stay, waiting for the Day of Judgment when they can enter Paradise.
The only ones who will ascend straight to heaven are the martyrs who die carrying out Jihad. Along with them will go their immediate family members. A Muslim mother who would normally have a large family therefore has a powerful incentive to want one of her sons to die as a martyr.
This will be a passport to heaven for her, her husband and the rest of her children. The alternative (being buried alive whilst waiting for the world to be conquered) is a fairly unappealing alternative. This is why Muslims will never allow their dead to be cremated.
HADITH Sahih Bukhari [4:52:177] Narrated Abu Huraira:
Allah's Apostle said, "The Hour will not be established until you fight with the Jews, and the stone behind which a Jew will be hiding will say, "O Muslim! There is a Jew hiding behind me, so kill him."
HADITH Sahih Muslim [41:6985] Abu Huraira reported Allah's Messenger (may peace be upon him) as saying:
The last hour would not come unless the Muslims will fight against the Jews and the Muslims would kill them until the Jews would hide themselves behind a stone or a tree and a stone or a tree would say: Muslim, or the servant of Allah, there is a Jew behind me; come and kill him; but the tree Gharqad would not say, for it is the tree of the Jews.
Muslims are encouraged by Islam to fight until the whole world is conquered, which will mark the end of the world. When this time arrives, all true Muslims will ascend to heaven. Those who refuse to participate in Jihad will face punishment from Allah and will be replaced by others who are more obliging.
From the Koran:
9:5 When the sacred months [by ancient Arab custom there were four months during which there was to be no violence] are passed, kill the Kaffirs wherever you find them. Take them as captives, besiege them, and lie in wait for them with every kind of ambush. If they submit to Islam, observe prayer, and pay the poor tax, then let them go their way. Allah is gracious and merciful.
9:38 Oh, believers, what possessed you that when it was said, “March forth in Allah’s cause [jihad],” you cling heavily to the earth? Do you prefer the life of this world to the next? Little is the comfort of this life compared to the one that is to come. Unless you march forth, He will punish you with a grievous penalty, and He will put another in your place. You will not harm Him at all, for Allah has power over everything.
Having read this far you should by now realize that this war (Jihad) hasn’t ended. Instead, it continues today in a more discreet form (in the West at least). If past Islamic history is a guide, this could be a precursor to the all-out military style Jihad, which is not yet feasible within the borders of Western nations.