In the Name of Allāh, the Ever Merciful, the Bestower of Mercy
Often the Shīʿah, in discussions with Muslims like to glaze over the hard facts that expose the shirk (polytheism), ghulū (extremism) and infatuation in their beliefs. Historically, Muslims, due to their for love for Tawḥīd and love for the Sunnah, would not tolerate them. However, with movements such as the ikhwān al-muslimīn and other politically motivated groups reaching out to them and blurring the difference between the sunnī and the Shīʿī, Muslims today often view them as our long lost cousins in Islām. Certainly not! Here is a small quote from their own books, that they cherish and reference: From that which they narrated as well in clarification of this principle according to them, is this narration: “Allāh has erected ʿAlī as a sign between Him and His creation. So whoever acknowledges it then he is a believer, while whoever rejects it then he is a disbeliever and due to his ignorance, he is astray. Whoever erects something along with him is a polytheist while whoever holds to his Wilāyah will enter Paradise.”1
1) Uṣūl al-Kāfī 1/437 Translated by Raha Batts
For further study on the deviation of the Shīʿah in aspects of tawḥīd see:
Amazing to find some Muslims today trivialising the affair of the shee'ah. I remember when I became Muslim, in the mid 90's, a brother in a masjid, witnessing a shee'ee praying in the sunnee masjid, becoming emotional, tears rolling down his cheeks asking the shee'ee, "say something about Aa'ishah, speak about her now, tell us!" and him having to be restrained and calmed down, whilst the shee'ee was escorted away.
At the time, I was unaware of their beliefs, but it struck me how moved this Arab brother was, and how much love he had for the Companions and the Mother of the Believers, 'Aa'ishah. It shocks me today to see Muslims either unaware or unconcerned about the beliefs of the shee'ah. Can one love Tawḥīd, love Allaah, love the Companions, hate shirk, hate bid'ah and be unmoved by the beliefs of this cult?
Then say: ‘O Muhammad!’ ten times; ‘O ‘Alee’ ten times; ‘O Faatimah’ ten times; ‘O Ḥasan’ ten times; ‘O Husayn’ ten times; ‘O ‘Alee ibn Al-Husayn’ ten times; ‘O Muhammad ibn ‘Alee’ ten times; ‘O Ja’far ibn Muhammad’ ten times; ‘O Mūsá ibn Ja’far’ ten times; ‘O ‘Alee ibn Mūsá’ ten times; ‘O Muhammad ibn ‘Alee’ ten times; ‘O ‘Alee ibn Muhammad’ ten times; ‘O Ḥasan ibn ‘Alee’ ten times; ‘O Hujjah’ ten times; then you ask Allaah the Exalted for your need.”