The Mahdi’s ascendancy to power is said to be preceded by an army from the east who will be carrying black flags or banners of war. Sheikh Kabbani states:
Hadith indicate that black flags coming from the area of Khorasan will signify the appearance of the Mahdi is nigh. Khorasan is in todays Iran, and some scholars have said that this hadith means when the black flags appear from Central Asia, i.e. in the direction of Khorasan, then the appearance of the Mahdi is imminent. 17
Another tradition states that:
The Messenger of Allah said: The black banners will come from the East and their hearts will be as firm as iron. Whoever hears of them should join them and give allegiance, even if it means crawling across snow.
In Islam there are two flags. One is white and one is black. Written across both flags in Arabic are the words, “There is no God but Allah and Muhammad is his Messenger”. The white flag is called Al-Liwaa and serves as the sign for the leader of the Muslim army and is the flag of the Islamic State. The black flag is called Ar-Raya and is used by the Muslim army. It is also called the flag of jihad, and is carried into battle. One flag is governmental and the other is a military flag.
When Muhammad returned to his home city of Mecca after being exiled for eight years, he returned as a conqueror. With him were ten thousand Muslim soldiers. They carried with them black flags. On the flags was one word written in Arabic: punishment.
The Conquering Of Israel
Islamic tradition pictures the Mahdi as joining with the army of Muslim warriors carrying black flags. The Mahdi will then lead this army to Israel and re-conquer it for Islam. The Jews will be slaughtered until very few remain and Jerusalem will become the location of the Mahdi’s rule over the Earth.
Rasulullah [Muhammad] said: "Armies carrying black flags will come from Khurasan. No power will be able to stop them and they will finally reach Eela (Baitul Maqdas in Jerusalem) where they will erect their flags."
In a particularly venomous manner, Egyptian authors, Muhammad ibn Izzat and Muhammd ‘Arif comment on the above tradition:
The Mahdi will be victorious and eradicate those pigs and dogs and the idols of this time so that there will once more be a caliphate based on prophethood as the hadith states… Jerusalem will be the location of the rightly guided caliphate and the center of Islamic rule, which will be headed by Imam al-Mahdi… That will abolish the leadership of the Jews… and put an end to the domination of the Satans who spit evil into people and cause corruption in the earth, making them slaves of false idols and ruling the world by laws other than the Shari’a [Islamic Law] of the Lord of the worlds.
There is a very famous tradition that is often quoted throughout the Islamic world that speaks of the Mahdi’s military campaign against Israel. The tradition is both sickening and very sobering:
The Prophet said… 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…