Had these mercenaries studied Islamic history carefully...
Had these mercenaries studied Islamic history carefully, they would have known that the first one who declared the idea of the return of the Messenger of God was 'Umar Ibn Al-Khattab. Muslim historians agree that 'Umar stood at the Mosque of the Prophet when the Prophet passed away and said: "There are hypocrite men who allege that the Messenger of God has died.
Certainly the Messenger of God did not die, but he went to his Lord as Moses, son of 'Imran, went to his Lord (for receiving the Heavenly commandments). By God, Muhammad will return as Moses returned, and he shall sever the hands and legs of the men who alleged that the Messenger of Allah has died." (Ibn Hisham, Al-Sirah al-Nabawiyyah, part 2, page 655) We cannot say that 'Umar took this idea from Abdullah Ibn Saba or any other person.
Ibn Saba did not even exist at that time, not even in the imagination of Sayf bin 'Umar al-Tamimi, who invented the entire allegation. The Shi'ite school of thought does not consider the Prophet's return a part of Islamic belief. If any Muslim believes in this, it would only be logical to say that the source of this doctrine is the second Caliph's speech on the day the Messenger of God died, rather than Ibn Saba.
The Doctrine Of Ali's Executorship The dividers of Muslims alleged that Ibn Saba is the one who invented the doctrine of Ali's executorship. Yet history testifies that the Messenger of God himself is the one who declared that Ali would be his executor.
Imam Ali reported the following: When the Qur'anic verse: "And warn your closest relatives" was revealed, the Messenger of God called me and said: "Ali, certainly Allah commanded me to warn my closest relatives, and I feel the difficulty of this mission. I know that when I confront them with this warning, I will not like their response." The Prophet invited the members of his clan to dine with him on a small amount of food and little milk. There were forty of them.
After they ate, the Prophet spoke to them: "Children of Abdul Muttalib, by God, I do not know of any young man from the Arabs who brought to his people better than I brought to you. I have brought to you the goodness of this world and the Hereafter. The Almighty commanded me to invite you to it.