If a born Muslim does not believe in Prophet Muhammad’s, sallallaahu alayhi wa sallam, followers (Caliphs), is he out of Islam?

All perfect praise be to Allaah, The Lord of the Worlds.  I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

The expression 'does not believe in the Caliphs' needs some clarification as to what the questioner means by it. Anyway, if what is meant is to say that the Caliphs were not Muslims or that they were misguided, then this takes the person out of the fold of Islam, because this is denying Allaah The Almighty and His Prophet, sallallaahu ‘alayhi wa sallam, who praised them and other Companions . Allaah The Almighty Says (what means): {And the first to embrace Islam of the Muhaajiroon (those who migrated from Makkah to Madeenah) and the Ansaar (the citizens of Madeenah who helped and gave aid to the Muhaajireen) and also those who followed them exactly (in Faith). Allaah is well-pleased with them as they are well-pleased with Him. He has prepared for them Gardens under which rivers flow (Paradise), to dwell therein forever. That is the supreme success.}[Quran, 9:100]

 The greatest of all who embraced Islam were the four Caliphs . Allaah The Almighty further Says (what means): {Indeed, Allaah was pleased with the believers when they gave their pledge to you (Muhammad) under the tree.}[Quran, 48:18] Among the Companions who gave their pledge to the Prophet, sallallaahu ‘alayhi wa sallam, were Abu Bakr, 'Umar, and 'Ali and the Prophet, sallallaahu ‘alayhi wa sallam, gave the pledge to himself on behalf of 'Uthmaan with his hand (putting one hand on top of the other while pronouncing the pledge, when there were rumors that 'Uthmaan was killed).

It is also confirmed that the Prophet, sallallaahu ‘alayhi wa sallam, said: “Thus you must adhere to my Sunnah and the way of the rightly-guided Caliphs. Hold to it and stick fast to it.” [Ahmad, Abu Daawood, At-Tirmithi and Ibn Maajah] So ruling that they were not Muslims or that they were misguided is denying all the previous texts.

Imaam Al-Qurtubi said, “There is no difference of opinion that it is an obligation to respect the Companions and that it is forbidden to insult them. There is no difference of opinion [among the scholars] that whoever says that they were not Muslims or were misguided, that he [who claims so] is a non-Muslim and must be killed, because he is denying what is proven in religion and he is belying Allaah and His Prophet, sallallaahu ‘alayhi wa sallam. The same ruling applies to the one who says that one of the Caliphs is a non-Muslim or that they were misguided.” Therefore, whoever says that one of the Caliphs was a non-Muslim or was misguided is out of the fold of Islam.

The excellence of the four Caliphs is known and proven with absolute evidences in the books of Sunnah (Prophetic tradition). Each and every one of the Caliph has virtues, outstanding traits and excellence, which necessitate saying that whoever insults them is a non-Muslim. May Allaah be pleased with them all, and may He join us with them in Paradise. For further details, please refer to Fatwa 86898.

Allaah Knows best.