Arabia was idolatrous when, six centuries after Jesus, Muhammad introduced the worship of the God of Abraham, of Ishmael, of Moses, and Jesus. The Ariyans and some other sects had disturbed the tranquility of the east by agitating the question of the nature of the Father, the son, and the Holy Ghost. Muhammad declared that there was none but one God who had no father, no son and that the trinity imported the idea of idolatry.
In a conquered country benevolence is not humanitarianism. It is a general political axiom that a conqueror must not inspire a good opinion of his benevolence until he has demonstrated that he can be severe with malefactors.
When you determine to risk a battle, reserve to yourself every possible chance of success, more particularly if you have to deal with an adversary of superior talent, for if you are beaten, even in the midst of your magazines and your communications, woe to the vanquished!