Ibn Taymiyyah's Battle against Innovators & Deviant Sects!

Shaikhul-Islam Ibn Taymiyyah dedicated a lot of effort towards refuting various innovative sects. He even physically challenged some individuals from the heretical Sufi sect, known as the Bataa'ihiyyah that indulged in feats like walking over fire to amaze the common masses. He proposed that he would walk on fire with them on the condition that they wash themselves first with vinegar and hot water. Their refusal exposed their folly, and Ibn Taymiyyah thus exposed the charlatans of the Bataa'ihiyyah sect.

[See, Majmoo al-Fatawa (11/456-457) and al-Bidayah wan-Nihayah (14/36)] He also refuted Muhiyyuddin Ibn Arabi and the heresy of Wahdat al-Wajood.

Ibn Hajr said, '… From the astonishing qualities of this man (i.e. Ibn Taymiyyah) was that he was the strongest amongst men against the people of innovation, the Rawaafidah, the Hululiyyah, and the Ittihaadiyyah, and his works on this are many and famous, and his fatawa on them cannot be counted… It is obligatory upon the one, who has donned the robe of knowledge and possesses intelligence that he consider the words of a man based upon his well-known books or from the tongues of those who are trusted to accurately convey his words - then to isolate from all of this what is rejected and warn from them with the intention of giving sincere advice and to praise him for his excellent qualities and for what he was correct in as is the way of the scholars.

If there were no virtues of Shaykh Taqi ad-Deen except for his famous student Shaykh Shams ad-Deen ibn al-Qayyim al-Jawziyyah, writer of many works, from which both his opponents and supporters benefited from then this would be a sufficient indication of his (ibn Taymiyyah's) great position. And how could it be otherwise when the Shafa'ee Imams and others, not to speak of the Hanbalees, of his time testified to his prominence in the (Islamic) sciences…' [From Ibn Hajr's endorsement of 'Radd al-Waafir' contained at the end]

With regards refuting the people of innovation and the danger they pose to the Muslims Ibn Taymiyyah said, 'When some people asked Imam Ahmad ibn Hanbal that they felt uneasy about criticizing people, he replied, 'If I were to remain silent, how would the ignorant masses know the truth from falsehood?' Those who introduce heretical writings which oppose the Qur'aan and the Sunnah and those who innovate in matters of worship, then it is obligatory that they be exposed and that the Muslims be warned against them - by unanimous agreement of the Muslims scholars. In fact, when Imam Ahmad bin Hanbal was asked about a person who fasted, prayed and secluded himself in the mosque for worship; if he was dearer to him than a person who spoke out against the innovators? He replied, 'When he fasts and prays and secludes himself, then he does so for the benefit of his own self. However, when he speaks out against the innovators, he does so for the benefit of the Muslims in general, and this is more virtuous.' 

So it is clear that openly opposing the innovators is of general benefit to the Muslims and is considered one of the types of struggles in the path of Allah. Since purifying the religion of Allah and defending it from their attacks is a collective obligation - as is agreed upon by the scholars. For, Allah did not raise up some people to oppose the innovators, then the religion would suffer harm, corruption and deviation. Indeed, this type of corruption is even greater then the corruption resulting from the disbelievers conquering the Muslims. Since when the disbelievers conquer the Muslims, they do not corrupt their hearts, or their religion, except after some time. Whereas, the innovators corrupt the hearts from the very beginning.' 

[Majmoo al-Fatawa (28/231-232)]