The Islamic armys retreat made Caesars army impudent...

The Islamic armys retreat made Caesars army impudent, and there was the fear that they would attack the Islamic capital any moment. So in the 9th year after Hijrah, the holy Prophet, commanding a large and equipped army, headed for the border of Damascus. In this hard and painful expedition, the Islamic army managed to recover its prestige and to renew its political life.

A few days before his fatal illness, the Prophet, may God bless him and his descendants, not being not fully contented with this partial victory, dispatched Usamah, the commander, and the Islamic army, to the borders of Damascus.

The second of the trio was Khosrow Parviz, the Iranian king, who, having received the Prophets letter got so angry that he contemptuously tore it to pieces, insolently dispelled the Prophets messenger and wrote a letter to his governor general in Yemen to arrest the Prophet and kill him if he refuses to surrender.

Although Khosrow Parviz died while the Prophet, may God bless him and his descendants, was still alive, the question of the independence of Yemen, a colony of Iran for years, was a concern of the rulers of Iran, and the Iranian politicians could never, out of conceit and pride, bear the existence of a power in their neighborhood.

The third danger was that of the Hypocrites, who acted as the fifth column among Muslims, always committing crimes and sowing the seeds of discord to the extent that once they decided to assassinate the Prophet on his way from Tabuk to Medina.

Some of them cherished the hope that after the Prophets death, the Islamic movement would come to an end and that they would all be relieved.[1] The hypocrites destructive power was so great that the Holy Quran speaks about it in the following chapters: al-`Imran, al-Nisa, al-Maidah, al-Anfal, al-Tawbah, al- [1] Derived from ayatullah Subhani's Foruq-e-Abadiyyat. `Ankabut, al-Ahzab, Muhammad (a.s), al-Fath, al-Mujadilah, al-Hadid, al-Munafiqun, and al-Hashr.

With so many powerful enemies in ambush, would it have been right for the Prophet of Islam if he had not appointed a successor to the religious and political leadership of the newly-established community? The social calculations demanded that the Prophet appoint a leader to prevent any kind of discord after him and to ensure the Islamic unity by creating a firm, strong and defensive front.