Likewise was the case of those who were burnt alive by ‘Alee ibn Abee Taalib.(1) Yet these ignorant ones affirm that whoever denies the Resurrection is to be declared an unbeliever and killed, even after saying laa ilaaha illallaah. They also affirm that whoever denies any of the pillars of Islaam is to be declared an unbeliever and killed, even if he has uttered the kalimah. So how is it that [uttering the kalimah] does not benefit a person when he denies a secondary [fundamental], but will benefit a person who denies tawheed; which is the very core of the Religion that the Messengers were sent with?
However, the enemies of Allaah do not understand the meaning of those ahaadeeth.”(2).
And he, rahimahullaah, also said: “As for [what is to be understood from] the hadeeth of Usaamah who once killed a person who declared himself to be a Muslim, because he thought that he only did so due to fear for his life and property.
Then whenever a person outwardly displays that he is a Muslim, it is obligatory to withhold from fighting him, unless it becomes absolutely clear that he has done something to oppose this [and for which Islaam requires that he be fought].
Allaah revealed about this [type of situation]:
“O you who believe! When you go out to fight in the Path of Allaah, verify the truth, and do not say to anyone who greets you by embracing Islaam: You are not a Believer.” [Soorah an-Nisaa 4:94].
So this verse proves that it is obligatory to withhold and to verify the truth. So if after investigation it is proven that the person contradicts Islaam, then that person is to be fought, because of Allaah’s command to verify the truth. If it was the case that a person could never ever be fought, so long as he has uttered the kalimah, then the command to verify the truth would be pointless! Likewise is the case for those other ahaadeeth that we have previously mentioned, which are similar in meaning [and which state] that whoever outwardly displays Islaam and tawheed, then it is obligatory to withhold concerning him, except if it becomes clear from him that he contradicts this. The proof for this is that the Messenger sallallahu alaihi wasallam said: “Have you killed him after he uttered laa ilaaha illallaah!”
And he said: “I have been ordered to fight the people until they say laa ilaaha illallaah.” (3).
Yet he is the one who also said about the Khawaarij:
“If I were to meet them, then I would kill them, as the people of Aad were killed.”(4).
[This was the case] even though they were the most persistent of people in uttering laa ilaaha illallaah, to the extent that even the Companions felt [that their own worship was] insignificant compared to theirs. The Khawaarij were also those who learnt knowledge from the Companions, yet their [utterance of] laa ilaaha illallaah did not benefit them, nor did their abundant worship, nor did their ascription to Islaam - since they displayed actions which were contrary to the Prescribed Law (Sharee’ah). Likewise is the case concerning fighting against the jews, and the Companions fighting against Banoo Haneefah, as we have previously mentioned.”(5).
(1) Reported by al-Bukhaaree (no.6922).
(2) Kashfush-Shubuhaat (pp.45-49).
(3) Reported by al-Bukhaaree (no.392) and Muslim (no.35).
(4) Reported by al-Bukhaaree (no.6930) and an-Nasaa’ee (no.3823).
(5) Kashfush-Shubuhaat (pp.49-51).