To understand the connection between Islam and violence, one must understand certain facets of the Muslim worldview. One of the most important is the fact that, according to the historic Muslim understanding, there is no separation between religion and government—what in Christianity would be called the separation of church and state.

We are not speaking here of the secularist idea that the state should marginalize religion and discourage people from voting their consciences as Christians. We are talking about the idea that church and state are not the same thing and that they have different spheres of activity.

This idea of a separation between religion and government is not characteristic of most peoples in world history. It is a contribution to the world of ideas that was made by Christians—indeed, by Christ himself. In his book Islam and the West, historian Bernard Lewis explains:

"The notion that religion and political authority, church and state, are different and that they can or should be separated is, in a profound sense, Christian. Its origins may be traced to the teachings of Christ, notably in the famous passage in Matthew 22:21, in which Christ is quoted as saying: ‘Render therefore unto Caesar the things which are Caesar’s; and unto God the things that are God’s.’ This notion was confirmed by the experience of the first Christians; its later development was shaped and in a sense even imposed by the subsequent history of Christendom. The persecutions endured by the early Church made it clear that a separation between the two was possible."

During much of Christian history church and state were united in that each Christian state had an official church, whether it was the Catholic Church or one of the Orthodox or Protestant churches. In many countries that is still the case. Nevertheless, the awareness remained that the two institutions were distinct and had different functions and different spheres of legitimate authority. They could in principle disagree and go their separate ways when necessary.

Most peoples in world history have not shared this understanding. In most societies, religion and government have been inseparably linked. This is true in Muslim society as well. Lewis explains:

"In pagan Rome, Caesar was God. Christians were taught to differentiate between what is due to Caesar and what is due to God. For Muslims of the classical age, God was Caesar, and the sovereign—caliph or sultan—was merely his viceregent on earth. This was more than a simple legal fiction. For Muslims the state was God’s state, the army God’s army, and, of course, the enemy was God’s enemy. Of more practical importance, the law was God’s law, and in principle there could be no other. The question of separating church and state did not arise, since there was no church, as an autonomous institution, to be separated. Church and state were one and the same."

This means that, in the historic Muslim understanding, Islamic society is or should be a theocracy—a society in which God himself is the monarch, reigning on earth through subordinates.

In the earliest days of Islam, the subordinate was the prophet Mohammed, who founded Islam and conquered the Arabian Peninsula. Thereafter the subordinate was the caliphs and in the centuries after Mohammed’s death they expanded Muslim society by conquering peoples as far west as Spain and as far east as India. In the process, they absorbed half of Christian civilization. Eventually, the power of the caliphs waned, and new leaders—such as the Ottoman sultans—were the subordinates. Throughout it all, God himself was regarded as the ruler of Islamic civilization.