Islaam and Muslims are not ruined except by the Khawaarij and Rawaafid (shiites)
Al-Allaamah Rabee Bin Haadi Al-Madkhalee (may Allaah preserve him) said:
By Allaah! Islaam and the [affairs of the] Muslims are not ruined except by these categories of [people] amongst the people of bidah and misguidance-the khawaarij and those similar to them, and those who are worse, such as the rawaafid [i.e. Shiites of Iran and those upon their beliefs].
The rawaafid are worse than the khawaarij, and Ikhwaan al-Muslimoon (i.e. the sect -the Muslim brotherhood in Egypt and elsewhere) ally with them and they say: “They (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 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 (rawaafid) have shir’kiyyaat (beliefs and acts of major polytheism) and they deify the leaders of the Prophet’s family. So does all of this not harm them (i.e. harm their claim to Islaam); is this not irjaa?! (i.e. O Ikhwaanis! Is this alliance of yours with the rawaafid and that the differing between you and them is like the differing between Imaams Maalik and Shaafi’ee not Ir’jaa?!)
[Source: الذريعة إلى بيان مقاصد كتاب الشريعة للإمام المحدث أبي بكر محمد بن الحسين الآجري pages: Page: 162][slightly paraphrased]