Shaykh `Abdul-Muhsin al-Abbaad – may Allaah preserve him – was asked on Thursday 16th Rabee`uth Thaanee 1436H, (coinciding with 5th February 2015CE):
Q: What do you say regarding that which Daa`ish (ISIS) have carried out by their burning of the [Jordanian] pilot; using as evidence [both] the speech of Shaykhul-Islaam ibn Taymiyyah, and their saying that it is permissible to seek vengeance from the enemy due to His saying:
وَإِنْ عَاقَبْتُمْ فَعَاقِبُوا بِمِثْلِ مَا عُوقِبْتُم بِهِ
And if you punish (your enemy, O Believers), then punish them with the like of that with which you were afflicted. [Sooratun-Nahl (16):126]
What is your advice? May Allaah preserve you.
A: These people are oppressive criminals, their actions are vile; and before this [incident] they would kill a person by slaughtering him with a knife – just as a sheep is slaughtered.
All of this is from exceeding the [legislated] bounds in seeking retaliation, and exceeding the bounds with regards to oppression, and carrying out a gruesome killing.
We say: this is not allowed – for no one punishes with fire except the Lord of the fire.
And killing – for those that deserve to be killed – is to be carried out in a way that is not sinful, & does not contain committing a forbidden act – there should be nothing impermissible involved.
These people [ISIS] themselves are not even upon uprightness, having with them matters that are ugly & go against the religion of Islaam.
Their origin that they [ISIS] are upon – is the same way as the Kharijites – those that declare the people to be disbelievers, and [they hold] that the people of major sins will remain in the Fire eternally.
This is from their actions, and their doing; and vengeance is not to be sought by committing forbidden acts.