Al-Allaamah Rabee Bin Haadi Al-Madkhalee (may Allaah preserve him) said:
By Allaah, Islaam and the Muslims are not ruined except by these categories of (people) amongst the people of bidah and misguidance–the khawaarij (i.e. such as ISIS etc) and those similar to them, and those who are worse than them, such as the Rawaafid (i.e. Rawaafid Shiittes of Iran, Iraq and elsewhere).
The Rawaafid are worse than the khawaarij. And Ikhwaan al-Muslimoon (i.e. the Muslim brotherhood sect in Egypt and elsewhere) ally with them and say: “They (i.e. rawaafid) are our brothers; the differing between us and them is like the differing between (Imaam) Maalik and (Imaam) Shaafi’ee”- meaning: The differing between us (i.e. Ikhwaan al-Muslimoon) and them (i.e. rawaafid shiites) is based on ijtihaad, and if Imaam (Maalik) and (Imaam) Shafee’ee differ in (some) affairs, they are all rewarded; and if we (ikhwaan al-muslimoon) differ with the rawaafid shiites, then us and them are rewarded.
O deceivers! (i.e. Ikhwaanis) The rawaafid (shiites) revile the Sahaabah and declare them disbelievers; they revile the wives of the Messenger (sallal-laahu-alayhi-wasallaam); they say that the Qur’aan is distorted; they have shir’kiyyaat (beliefs and acts of polytheism) and they deify the leaders of the Prophet’s family. So does all this not harm them (i.e. harm their claim to Islaam)? Is this not irjaa?! (i.e. O Ikhwaanis! Is this not Irjaa that you consider the differing between you and them to be similar to the differing between Imaams Maalik and Shaafi’ee)
[Source: الذريعة إلى بيان مقاصد كتاب الشريعة للإمام المحدث أبي بكر محمد بن الحسين الآجري pages: Page: 162]