A majority of Shias do not know that the following teachings are a part of their faith and in their religious books:
 Chapter: The Imams have knowledge of All that was given to the angels and the prophets. ( AlKafi vol.1 p.255 )
 Chapter: The Imams know when they will die, and they only die by their choice. ( AlKafi vol.1 p.258 )
 Chapter: The Imams have knowledge of the past and future; and nothing is hidden from them. ( AlKafi vol.1 p.260 )
 “Obedience to `Ali is true humility and disobedience to him is disbelief in Allah” ( AlKafi vol.10 p.54 )
 “Whoever sets up another Imam besides `Ali and delays `Ali’s caliphate is a polytheist” ( AlKafi vol.10 p.55 )
 The false verse “And We made `Ali your in-law” has been added to Surah Al-InShirah . ( AlKafi p.289 )
 Alkileeni reported that Jabir asked AbuJa`far p.b.u.h : “Why `Ali ibn Aby Talib was named Amir-ul-Mumineen?” AbuJa`far replied : “Allah named him so, and He revealed in His Book ” And (remember) when your Lord brought forth from the Children of Adam, from their loins, their seed and made them testify as to themselves (saying): Am I not your Lord, Muhammad my messenger and `Ali Amir-ul-Mumineen ?…” ( AlKafi vol.1 p.412 )
 “Abu Baseer reported that he said to Imam Ja’far, “O Abu Abdullah(Imam Ja’far as-Sadiq) What is Mus-haf Fatimah?” He replied “It is a Qur’an containing three times what is found in your copy of the Qur’an; yet by Allah, it does not contain even a single letter from your Qur’an. ( AlKafi vol.1 p.457 )
 After making muta Once – The stage of Hussain is reached. After making muta twice – The stage of Hasan is reached. After making muta three times – The stage of Ali is reached. After making Muta Four times- The stage of Rasulullaah is reached. (Tafseer Mianjajus Sadiqeen 1:356.)
 Contractors of ‘Muta’ will cross the ‘Pul Siraat’ like a flash of lightning.( Ujul – e- Hasana P17)
These beliefs differ from several principles in the Quran, as a commenter points out:
In response to Shia teachings 1-3, the Quran states in Surah Luqmaan “Verily, Allah With Him (Alone) is the knowledge of the Hour, He sends down the rain, and knows that which is in the wombs. No person knows what he will earn tommorow, and no person knows in what land he will die. Verily, Allah is All-Knower, All-Aware (of things)” [Quran 31:34]
As for Shia teachings 4-5, these words declare all AhlSunnah as kufaar (Disbelievers) for accepting Ali’s caliphate to be the 4th following Abubakr, Omar and Othman. This begs the question, would Ali name his own children after people who wronged him while he did not have love for them in his heart?
Hadrat Ali’s first wife was the most beloved daughter of the Holy Prophet, Hadrat Fatimah (R.A.). He got three sons (Hasan, Husain and Muhsin), and two daughters (Zainab and Umm-i-Kulthum) from her. The youngest son, Muhsin died in childhood.
After the death of Hadrat Fatimah, Ali married a number of wives from time to time:
(b) Umm al-Banin bin Hizam from whom Ali got ‘Abbas, Ja’far, ‘Abdullah and Uthman. All of these except Abbas were martyred at Karbala.
(c) Saila bint Mas’ud who gave birth to ‘Ubaidullah and Abu Bakr. They were martyred at Karbala.
(d) Asma bint Umais who gave birth to Yahya and Muhammad Asghar.
(e) Sahba bint Rabi’a who gave birth to Umar and Ruqayyah. Amamah bint Abil ‘As: She was daughter of Zainab (R.A.), daughter of the Prophet (Sallallahu ‘alaihi we Salaam). Hadrat Ali got Muhammad Aswat from her.
(g) Khaulah bint Jalfar who gave birth to Muhammad ibn
(h) Umm-i-Sa’id who gave birth to Ummul Hasan and Ramlah Kubra.
(i) Mahyah bint Ummul Qais, she gave birth to a daughter who died in childhood.
As for Shia teachings 7-8, “Muhammad my messenger and `Ali Amir-ul-Mumineen” is not part of the Quranic verse [Quran 7:172]. Moreover, the Quran clearly states “And he [Muhammad PBUH] is not a withholder of the (knowledge of the) unseen (to the people).” [Quran 81:25].
As for Shia teachings 9-10, a temporary marriage contract is not permissible in Islam.
An excellent article on Why Are Muslims Divide Into Sects, available here
The question sometime arises…if all the Muslims follow one and the same Qur’an then why are there so many sects among them?
There are several points to consider in answering this question:
1. Muslims should be united
It is a fact that Muslims today are divided amongst themselves. The tragedy is that such divisions are not endorsed by Islam at all. Islam believes in fostering unity amongst its followers.
The Glorious Qur’an says:
And hold fast, all together, by the rope which Allah (stretches out for you), and be not divided among yourselves;” [Al Qur’an 3:103]
Which is the rope of Allah that is being referred to in this verse? It is the Glorious Qur’an. The Glorious Qur’an is the rope of Allah which all Muslims should hold fast together. There is double emphasis in this verse. Besides saying ‘hold fast all together’ it also says, ‘be not divided’.
The Qur’an further says:
Obey Allah, and obey the Messenger. [Al Qur’an 4:59]
All the Muslims should follow the Qur’an and authentic ahadith and be not divided among themselves.
2. It is prohibited to make sects and divisions in Islam
The Glorious Qur’an says:
As for those who divide their religion and break up into sects, thou hast no part in them in the least: Their affair is with Allah: He will in the end tell them the truth of all that they did. [Al Qur’an 6:159]
In this verse Allah (Praised and Glorified) says that one should disassociate oneself from those who divide their religion and break it up into sects.
But when one asks a Muslim, “who are you?”, the common answer is either ‘I am a Sunni, or ‘I am Shia’. Some call themselves Hanafi, or Shafa’ee or Maliki or Hambali. Some say ‘I am a Deobandi’, while some others say ‘I am a Barelvi’.
3. Our Prophet (peace and blessings of Allah be upon him) was a Muslim
One may ask such Muslims, “what was our beloved prophet (peace and blessings of Allah be upon him)? Was he a Hanafi or a Shafa’ee, or a Hambali or a Maliki?”
No! Muhammad was a Muslim, like all the other prophets and messengers of Allah before him.
It is mentioned in Chapter 3 Verse 52 of Al Qur’an that Jesus (peace and blessings of Allah be upon him) was a Muslim.
Further, in Chapter 3 Verse 67, Al Qur’an says that Ibraheem (peace and blessings of Allah be upon him) was not a Jew or a Christian but was a Muslim.
4. Qur’an says call yourselves Muslim
If anyone poses a Muslim the question who are you, he should say “I am a MUSLIM, not a Hanafi or a Shafa’ee”. Surah Fussilat Chapter 41 Verse 33 says
Who is better in speech than one who calls (men) to Allah, works righteousness, and says, ‘I am of those Who bow in Islam (Muslim)?’[Al Qur’an 41:33]
The Qur’an instructs adherents to “Say I am of those who bow in Islam”. In other words, say, “I am a Muslim”.
Moreover, the Prophet (peace and blessings of Allah be upon him) dictated letters to non-Muslim kings and rulers inviting them to accept Islam. In these letters, he mentioned the verse of the Qur’an from Surah Al Imran Chapter 3 Verse 64:
Say ye: “Bear witness that we (at least) are Muslims (bowing to Allah’s Will). [Al Qur’an 3:64]
5. Respect all the great Scholars of Islam
We must respect all the great scholars of Islam, including the four Imaams, Imam Abu Hanifa, Imam Shafa’ee, Imam Humbal and Imam Malik (may Allah have mercy on all of them). They were great scholars and may Allah reward them for their research and hard work. One can have no objection if someone agrees with the views and research of Imam Abu Hanifa or Imam Shafa’ee, etc. But when posed a question, ‘who are you?’, the reply should only be ‘I am a Muslim’.
6. The Counter-argument
Some may argue by quoting the hadith of our beloved Prophet (peace and blessings of Allah be upon him) from Sunan Abu Dawood, Vol. 5 Hadith 4596. In this hadith, the prophet is reported to have said, “My community will be split up into seventy-three sects.”
This hadith reports that the prophet(pbuh) predicted the emergence of seventy-three sects. He did not say that Muslims should be active in dividing themselves into sects. The Glorious Qur’an commands us not to create sects. Those who follow the teachings of the Qur’an and Sahih Hadith, and do not create sects are the people who are on the true path.
According to Tirmidhi, Vol. 5, Hadith 2641, Abdullah ibn Amr narrated that the Messenger of Allah (pbuh) said, “My Ummah will split into seventy-three sects. All of them are in the Fire except one sect”. He said: “And which is it O! Messenger of Allah?” He said: “What I am upon and my Companions.”
The Glorious Qur’an mentions in several verses, “Obey Allah and obey His Messenger”. A true Muslim should only follow the Glorious Qur’an and the Sahih Hadith. He can agree with the views of any scholar as long as they conform to the teachings of the Qur’an and Sahih Hadith. If such views go against the Word of Allah, or the Sunnah of His Prophet, (pbuh) then they carry no weight, regardless of how learned the scholar might be.
If only all Muslims read the Qur’an with understanding and adhere to Sahih Hadith, InshAllah most of these differences would be solved and we could be one united Muslim Ummah.