They quote a hadith in which Muhammad is depicted as saying “that you not leave an elevated grave without levelling it, nor an image without erasing it.” They are, then, acting in accord with his words when they commit these acts of savagery. Will “moderate” spokesmen in the West explain how they’re misunderstanding Muhammad here? Don’t count on it.
“Islamic State (ISIS) Destroys Christian Graves In Mosul,” MEMRI, April 16, 2015:
The following report is a complimentary offering from MEMRI’s Jihad and Terrorism Threat Monitor (JTTM). For JTTM subscription information, click here.
On April 16, 2015, the information office for the Islamic State (ISIS) in Ninawa Province, Iraq, published a series of photos titled “Levelling Graves and Erasing Polytheist Symbols.” The photos, which were posted on the Shomoukh Al-Islam jihadi forum, among other places, show ISIS members shattering gravestones with sledgehammers and defacing crosses carved into them. The photos are prefaced by the religious justification for ISIS’s actions – a hadith determining that any grave higher than ground level must be shattered and any images on it must be erased: “Ali bin Abi Taleb said to Al-Hayyaj Al-Asadi: ‘I am dispatching you with what the Prophet dispatched me: That you not leave an elevated grave without levelling it, nor an image without erasing it.'”
That’s from Jami` at-Tirmidhi 10.85.1049.