"Some believe that, for a Muslim to have religiously correct worship and dealing, it is necessary to follow one of the four known schools of thought. Is it true?"
Islam does not require a Muslim to follow a particular Madh'hab (school of thought). Rather, we say: every Muslim has the right to follow one of the schools of thought which has been correctly narrated and its verdicts have been compiled in its books. And, everyone who is following such Madhahib [schools of thought] can transfer to another school, and there shall be no crime on him for doing so.Since the religion of Allah and His Divine Law (Shari'ah) was never restricted to a particular school of thought.
The Origins of Shia and Sunni that splits Islam in the Arabic world.
After the death of our beloved prophet, Nabi Muhammad saw, mark the days of the "Caliphate"[means the Leader of Islam Ummah].
The Central figure of the split was Ali, cousin of the Prophet, husband of this daughter Fatima, father of Hassan and Hussein and finally the 2nd person ever to convert/embrace to Islam.
The Shia shahadah (declaration of faith) states:
"There is no god but Alláh, Muhammad is the Messenger of Alláh, Alí is the Friend of Alláh. The Successor of the Messenger of Alláh And his first Caliph."
This means that the Shia believe that Ali is the rightful First Caliphs, the successor of Nabi Muhammad saw and the caliphate should pass down only to direct descendants of Mohammed (pbuh) via Ali and Fatima.They often refer to themselves as ahl al bayt or "people of the house" [of the prophet].
The Sunni doesnt recognise this.Sunnis regard Ali as the fourth and last of the "rightly guided caliphs" following on from Abu Bakr (632-634), Umar (634-644) and Uthman (644-656).
Abu Bakr was appointed to be the First Caliphs.
After Muhammad's death, previously dormant tensions between the Meccan immigrants, the Muhajirun, and the Medinan converts, the Ansar, threatened to break out and split the Ummah. The Ansar, the leaders of the tribes of Medina, met in a hall or house called saqifah, to discuss whom they would support as their new leader. When Abu Bakr was informed of the meeting, he, Umar, Abu Ubaidah ibn al-Jarrah and a few others rushed to prevent the Ansar from making a premature decision. Accounts of this meeting vary greatly. All agree that during the meeting Umar declared that Abu Bakr should be the new leader, and declared his allegiance to Abu Bakr, followed by Abu Ubaidah ibn al-Jarrah and Abu Bakr became the first Muslim caliph, who was given the title, Khalifa-tul-Rasool (Successor of messenger of Allah), a title only accepted by Sunni muslims.
After the meeting at saqifah, the Muslims who were not present were asked to submit to Abu Bakr, to give their pledge of allegiance. Most accounts agree that Ali(Muhammad's beloved companion, cousin and son-in-law) and his supporters initially refused to submit. After a period of time, the duration of which is disputed, the dissidents gave their bay'ah. Whether or not the process involved violence and intimidation, and whether or not Ali willingly swore allegiance to Abu Bakr have remained enduring controversies.
Then the tittle of the Caliphs was passed down to Umar[632-634], then Uthman[644-656] and finally Ali.
After the death of the Ali [the 4th Caliphs], it marks the end of the Rightly Guided Caliphs.
The line of Mohammed (pbuh)through Ali and his son Hussein became extinct in 873CE when the last Shia Imam, Muhammad al-Mahdi, who had no brothers disappeared within days of inheriting the title at the age of four. He is the Twelth and final Imam and it is believe he is still alive. He is in a state of occultation. He will reappear at a moment determined by Alláh. He is the Awaited One who will spread justice throughout the world. He is believe to be the "Imam Mahdi" which is stated in the Al-Quran Mukarim who will fight side by side with Isa Al-Messiah against the Dajjal in time to come.
UnforgivenCurse