4. After Muhammad died, the people who lived with him, and knew his religion best, immediately fell into war with each other.
Muhammad's favorite daughter, Fatima, and her husband, Ali (the second convert to Islam, who was raised like a son to Muhammad) fought a war against an army raised by Aisha, Muhammad's favorite wife - and one whom he had said was the "perfect woman."
Not only was her husband, Ali, eventually murdered, but Fatima (who survived the early years at Mecca safe and sound) died of stress from the persecution of fellow Muslims only three months after her father died.
Three of the first four Muslim rulers (caliphs) were murdered. All of them were among Muhammad's closest companions. The third caliph was killed by the son of the first. The fourth caliph was killed by the fifth, who subsequently poisoned one of Muhammad's two favorite grandsons. Muhammad's other grandson was later beheaded by the sixth caliph.
Even these high profile killings barely do justice to the astonishing level of violence taking place at the time, in which tens of thousands of believers were slaughtered by Muhammad's companions and their children in the infighting and power struggles. Within 50 short years of Muhammad's death, even the Kaaba, which had stood for centuries under pagan religion, lay in ruins from internal Muslim war.
And that's just the fate of those within the house of Islam!
5. Muhammad directed Muslims to wage war on other religions and bring them under submission to Islam. Within the first few decades following his death, his Arabian companions invaded and conquered Christian, Jewish, Hindu, Buddhist and Zoroastrian lands.
A mere 25 years after Muhammad's death, Muslim armies had captured land and people within the borders of over 28 modern countries outside of Saudi Arabia.
6. Muslims continued their Jihad against other religions for 1400 years, checked only by the ability of non-Muslims to defend themselves. To this day, not a week goes by that Islamic fundamentalists do not attempt to kill Christians, Jews, Hindus and Buddhists explicitly in the name of Allah.
None of these other religions are at war with each other.
7. Islam is the only religion that has to retain its membership by threatening to kill anyone who leaves. This is according to the example set by Muhammad.
8. Islam teaches that non-Muslims are less than fully human. Muhammad said that Muslims can be put to death for murder, but that a Muslim could never be put to death for killing a non-Muslim.
9. The Qur'an never once speaks of Allah's love for non-Muslims, but it speaks of Allah's cruelty toward and hatred of non-Muslims more than 500 times.
10. "Allahu Akbar! Allahu Akbar! Allahu Akbar!"
(The last words from the cockpit of Flight 93). Translated means "God is great". It is a common Arabic expression, used as both an informal expression of faith and as a formal declaration to show of love of Islam and hatred for all that is not.