Shaykh Rabīʿ bin Hādī wrote:

All praise is due to Allāh and may ṣalāt and salām be upon Allāh’s Messenger, upon his family, his companions and whoever followed his guidance, to proceed: Then its known regarding [the viewpoint of] Ahl us-Sunnah that the one who falls into a nullifier [of Islām (mukaffir)] is not to be declared an unbeliever until the proof is established upon him. As for the one who falls into innovation then [he is] of [various] types:

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