I answer that, with regard to heretics, two points must be observed: one, on their own side; the other, on the side of the Inquisition. On their own side there is the sin, whereby they deserve not only to be separated from the Imperium by excommunication, but also be severed from the world by death. For it is a much graver matter to corrupt the faith which quickens the soul, than to forge money which supports temporal life. Wherefore if forgers of money and other evildoers are forthwith condemned to death by the secular authority, much more reason is there for heretics, as soon as they are convicted of heresy, to be not only excommunicated but even put to death.
— Inquisitor Verelius, Warhammer 40,000, based from a quote by Thomas Aquinas
It is not our place to forgive the heretic, only to pray for his unworthy soul as his ashes ascend from the pyre.
— The Book of Castigations, Warhammer 40,000
The Dragonborn: I can worship whoever I want.
Thalmor Justiciar: Incorrect. You can worship any gods you like. But Talos is a man, and only a heretic would think otherwise. And so you will die a heretic's death.
(an Imperial Guardsman picks up a lewd magazine)
Commissar: (bursts into the room) You have sullied your hands with filthy parchments of heresy, Guardsman! How do you plead?
Guardsman: What? No!
Commissar: Too late, heretic! *BLAM!*
(the Commissar picks up the magazine)
Space Marine: (bursts through the door) You inspire your men to study such foul smut, Commissar? YOU HERETIC! *BLAM!*
(the magazine lands on the Space Marine's helmet)
Sister of Battle: (bursts through the door) You detestable mutants fill your heads with such vile obscenity?! DIE, HERETIC! *rapid-fire BLAM*
(The Sister picks up the magazine)
Sister of Battle: Maybe just... one read....
Grey Knight: (bursts through the door) Sister, I need your blood to- Wait, hold on. You're a heretic! *BLAM-BLAM-BLAM*
Inquisitor: (in orbit) You know what, they're just running around shooting each other down there... better just lay the Exterminatus upon these heretics. ALRIGHT, FIRE! *headbutts the Exterminatus button*
