In the face of this bloody chaos, the proponents of irja said that the burning question of who is a true Muslim should be “postponed” until the afterlife. Even a Muslim who abandoned all religious practice and committed many sins, they reasoned, could not be denounced as an “apostate.” Faith was a matter of the heart, something only God — not other human beings — could evaluate.

The scholars who put this forward became known as “murjia,” the upholders of irja, or, simply, “postponers.” The theology that they outlined could have been the basis for a tolerant, noncoercive, pluralistic Islam — an Islamic liberalism. Unfortunately, they did not have enough influence on the Muslim world. The school of thought disappeared quickly, only to go down in Sunni orthodoxy’s memory as one of the early “heretical sects.” The murjia left a mark on the more lenient side of Sunni Islam, represented by Hanafi-Maturidism, most popular in the Balkans, Turkey and Central Asia, but today there is virtually no Muslim group that identifies itself as murjia. The word irja is seldom heard in discussions of Islamic theology.

So why is the Islamic State so alarmed about this old “heresy”? The answer to this question can be found in the Dabiq article itself, where the authors accuse other Islamist rebel groups in Syria of irja. “These factions did not rule by the Shariah despite their control of ‘liberated’ territory,” the Islamic State writers note loathingly. In other words, they did not kill “apostates,” implement corporal punishment, or force women to cover themselves head to toe.