From appearance, it is difficult to distinguish between the adherents of Islam and Shi'ah. However, once examined more deeply, especially in terms of aqeedah, the difference between the two is like oil and water. Making it impossible for them to be united.

Shi'ah, according to the etymology of Arabic language, means advocates and followers of someone, besides that it also means every people who gather on a matter. ("Tahdzibul Lughah", 3/61 written by Azhari and "Taajul Arus", 5/405, written by Az-Zabidi).

As for the meaning according to the terminology of shari'ah, Shi'ah means those who assert that Ali bin Abu Thalib is more important than the entire Sahabahs and more entitled to become a khalifah of the Muslims ("Al-Fisal Fil Milali Wal Ahwa Wan Nihal" written by Ibnu Hazm).

Shi'ah started to emerge after the killing of Khalifah Utsman bin ‘Affan. In the time of caliphate of Abu Bakar and Umar, and the early days of the caliphate of Uthman i.e. during the early years of his post, the Islamic Ummah was united, there was no dispute. And then at the end of the caliphate of Uthman, there were various events that resulted in the onset of the split, a group of fitnah and atrocity makers emerged, they murdered Uthman, that resulted in the division in the Islamic Ummah.

In the time of the caliphate of Ali, the Shi'ah group existed but they concealed their orientation, they did not make it visible to Ali and his followers.

At that time they were divided into three categories.

Shi'ah/The group that considers Ali bin Abi Thalib God.

When knowing about this sect, Ali burned them and made trenches in front of the door of the masjid of Bani Kandah to burn them. Imam Bukhari narrated in his saheeh book, from Ibnu Abbas he said, "At one time, Ali fought and burned those people of zindiq (the Shi'ahs who deified Ali). If I were to do it, I would not burn them because the Prophet ever prohibited a punishment like the punishment of God (burning), but I would definitely chop off their head, because the Prophet said:"Whoever replaces his religion (becomes murtad), kill him."

Shi'ah Sabbah (insulters).

Ali heard about Abu Sauda (Abdullah bin Saba') that he had insulted Abu Bakr and Umar, so Ali looked for him in order to kill him, but he ran away.

Shi'ah /The Mufadhdhilah group, i.e. those who give top priority to Ali over Abu Bakr and Umar.

Whereas, it had been narrated in mutawatir by Prophet Muhammad that he said: "The best of the people after the Prophet are Abu Bakar and Umar".

A riwaayah of this kind was brought by Imam Bukhari in his saheeh book, from Muhammad bin Hanafiyyah that he asked his father, who are the best humans after of Rasulullah , he answered Abu Bakr, and then who? He answered, Umar.

In the history of Shi'ah they are divided into five major sects, namely:

1. Kaisaniyyah
2. Imamiyyah (Rafidhah)
3. Zaidiyyah
4. Ghulat 
5. Ismailliyah

And from these five sects, so many branches of other sects were born.

Out of those five sects, the most important to be raised is the imamiyyah or rafidhah sect, which for a long time until now always fight hard to destroy Islam and the Muslims. In various ways, this group continue to work hard to spread a wide range of its misguidance, especially after the establishment of the Shi'ah state, Iran which toppled the regime of Shah Reza Pahlevi.

- Rafidhah according to the Arabic language means abandoning, while in the terminology of Shari'ah it means those who reject the leadership of Abu Bakr and Umar, who free themselves from them both, and those who reproach and insult the Sahabahs of the Prophet.

Abdullah bin Ahmad bin Hanbal said, "I have asked my father, who are the Rafidhahs?" So he answered, "They are the people who reproach Abu Bakr and Umar." ("as-Sarimul Maslul ‘Ala Shatimir Rasul" pg. 567, Sheikhul Islam Ibnu Taimiyah)

- The term "Rafidhah" is closely related with Zaid bin ‘Ali bin Husain bin ‘Ali bin Abu Thalib and his followers during the revolt against Hisham bin Abdul Malik bin Marwan in the year 121 H. ("Badzlul Majhud", 1/86)

Sheikh Abul Hasan al-Ash'ari said, "When Zaid bin ‘Ali appeared in Kufah, in the midst of the followers who gave him bai'ah, he heard from some of them censures against Abu Bakr and ‘Umar. He then negated it, until in the end they (his followers) left him. So he said to them: "You are leaving me?"

Then it was said that the naming of them with "Rafidhah" was due to the words of Zaid for them "Rafadhtumuunii." ("Maqalatul Islamiyyin", 1/137). The same thing was also said by Sheikhul Islam Ibnu Taimiyah in "Majmu' Fatawa" (13/36).

- The originator of the Shi'ah doctrine was a Jew from Yemen named Abdullah bin saba' al-himyari, who showed his Islam during the caliphate of Uthman bin Affan.

Abdullah bin Saba' introduced his teachings openly, he then rallied the masses, announcing that the leadership (imamah) after Prophet Muhammad should fall into the hands of Ali bin Abi Thalib as per the instruction of the Prophet sallallahu ‘alaihi wa sallam (according to their reckoning).

- According to Abdullah bin Saba', Khalifah Abu Bakr, Umar and Uthman had taken over that position. In "Majmu' Fatawa", 4/435, it was mentioned that Abdullah bin Saba showed an extreme attitude in glorifying Ali, with one slogan that Ali is the one who has the right to be the imam (khalifah) and he was one who is ma'sum (immune from all sins).

That belief developed constantly from time to time, to the extent of deifying Ali bin Abi Thalib. Ali, who knew about the excessive attitude later fought, in fact even burned those who did not want to repent, some of them escaped.

- Abdullah bin Saba', the founder of this Shi'ah religion, was a Jewish agent who was rotten and full of plots. He was inserted in the midst of the Muslims by the Jews to corrupt the religious order and Muslim community. His early appearance was the end of the leadership of the Khalifah ‘Uthman bin ‘Affan. And then continued during the leadership of a Khalifah ‘Ali bin Abi Thalib.

Under the guise of Islam, the spirit of amar ma'ruf nahi mungkar and masked in tanassuk (active worshiping), he packaged his various evil missions. It was not just the astray aqeedah (in fact kufr) that he conveyed in the midst of the ummah, he also provoked the masses to overthrow Khalifah ‘Uthman bin ‘Affan. As a result, the Khalifah was unjustly killed. As a result again, conflict of opinions among the Sahabahs also occurred. (See "Minhajus Sunnah" by Sheikhul Islam Ibnu Taimiyyah, 8/479, "Sharh Al-‘Aqidah Ath-Thahawiyyah" by Ibnu Abil ‘Izz pg. 490 and "At-Tauhid" by Ash-Sheikh Shalih bin Fauzan Al-Fauzan pg. 123).

- The Rafidhahs must be Shi'ah, while the Shi'ahs do not have to be Rafidhah. Because not all Shi'ahs hate Abu Bakr and ‘Umar like the Shi'ah Zaidiyyah, a Shi'ah sect that has the lightest errors.

[Arranged from various sources, which includes "Al-Furqon Bainal Haq Wal Batil" written by Sheikhul Islam Ibnu Taimiyyah)