If Christianity were true religious persecution would become a pious and charitable duty: if God designs to punish men for their opinions it would be an act of mercy to mankind to extinguish such opinions. By burning the bodies of those who diffuse them many souls would be saved that would otherwise be lost, and so there would be an economy of torment in the long run. It is therefore not surprising that enthusiasts should be intolerant.
"Religion", p. 178. - The Martyrdom of Man (1872)