1. The Twelve Imams
Shi’a believe the true successors of Prophet Muhammad (P) are twelve Imams of Ahlul-Bayt (a.s). They are: Imam Ali, Imam Hasan, Imam Husain, Imam Sajjad, Imam Baqir, Imam Sadiq, Imam Kadhem, Imam Redha, Imam Jawad, Imam Hadi, Imam Askari and Imam Mahdi (a.s).
In about 270 Hadith from the Shi’a and Sunni sources it is narrated from the Prophet of Islam (P) to have said: “The Imams will be twelve according to the number of the Twelve Leaders of Bani-Israel.”
For instance, Salman al-Farsi (r) narrated from the Prophet (P): “The Imams after me are according to the number of the Princes of Israelites and they were twelve.” Then the Prophet (P) put his hand on Husain (a.s) and said: “There will be nine from his offspring and the ninth is their Mahdi who will spread justice on earth as it is filled up with injustice and oppression, so vow to their enemies.” [al-Majlesi, Beharul-Anwaar, vol. 36 p.290]
2. Infallibility of the Twelve Imams and Fatima (a.s)
The Shi’a believe in 14 infallible people, i.e. Prophet Muhammad (P), Fatima al-Zahra, his daughter, and the twelve Imams. One of the proofs for their infallibility is Ayah 33 of Surah al-Ahzab (33).
Most Sunni scholars by contrast suggest that the Ayah includes the wives of the Prophet as part of the ‘Family of the House.’ Their main reasons are firstly the fact that the Ayah under consideration is amidst the Ayah that is dealing with the wives of the Prophet (P), and secondly, they rely on a Hadith that is allegedly narrated from Ekrema saying: “It is meant for the wives of the Prophet (P).”
Ekrema was inclined towards al-Khawarej; a fanatic military group opposing Imam Ali (a.s). The experts in narratology have also regarded him as a “liar”.
Moreover, Muslim in his Sahih [vol4. p.1873, 1874] has excluded the wives of the Prophet (P). Even the wives of the Prophet (P) themselves have confessed in many narrations that they were not included in that special meaning of the ‘Family of the Household’.
Believing in al-Mahdi as the last saviour from the offspring of the Prophet (P) is quite unanimously accepted by all Muslims. There are about 400 Hadith in the Sunni books of Hadith confirming the coming of al-Mahdi. The main difference between the Sunni and the Shi’a about Mahdi is that the Shi’a, unlike the Sunnis, believe that Imam Mahdi is -by the Leave of God – alive. He was born in the year 255 AH and his father was the eleventh Imam; Imam Askari. This concept is compatible with the concept of the Twelve Imams as well as the unanimously accepted Hadith “Whoever dies not knowing the Imam of his/her time has died the death of Jahiliyah (polytheism).”
4. Seeking Help (al-Tawassul) and Intercession (al-Shafa’a)
Al-Tawassul, or seeking help, means to seek the help of God through the means He has introduced and allowed us to utilize. Allah; the Almighty states in the Quran: “O you who believe! Be pious and ask the means of approach to Him.” [5:35]
Al-Shafa’a, or intercession, also means to seek the intercession of those to whom Allah – due to their exalted status – has granted the power to intercede; such as the Prophet of Islam (P) and his infallible successors. The Holy Quran, whilst rejecting the intercession of the idols, confirms the intercession of those whom Allah has allowed them to intercede: “On that Day no intercession shall avail, except the one for whom the Most Gracious (Allah) has given permission and whose word is acceptable to Him.” [20:109]
Apart from the Wahabi sect, the absolute majority of Muslims believe in the concept of al-Tawassul and al-Shafa’a.