Matthew 10:1 says, "Then Jesus summoned his twelve disciples and gave them authority over unclean spirits, to cast them out, and to cure every disease and every sickness" (NRSV).
In the Greek, the passage says that Jesus gave his disciples authority over unclean spirits in order to cast them out and cure disease.
What's that mean? The disciples' authority over unclean spirits enabled them to heal the sick. And what's that mean? That Matthew attributes disease and sickness to demons.
There are places in the New Testament in which this is more explicit. In Matthew 9:32-33, Jesus heals a mute person, whose condition was caused by demons. In Luke 13:11-16, Jesus heals a woman who was bent over and crippled because of Satan. And Paul had a thorn in his flesh that he calls "a messenger of Satan" (II Corinthians 12:7).
I wrote to a fellow Hebrew Union College student who is now a professor. I once took a class from him about demons, so I thought he'd know something about how the ancients viewed disease. "Did they attribute diseases to demons?" I asked him. After the customary pleasantries, he replied as follows:
"Literature from the Ancient Near East indicates that demons were blamed for any number of physical and mental ailments. There are, of course, gospel accounts in which someone is simply described as sick, incapacitated, or dead, without mention of a demon or evil spirit, and there are explicit exorcisms as well. But overall, my take has always been that illness in general was attributed to demonic forces during ancient times–-I don’t know enough about classic Greek thought to suggest whether their views were different, but as far as Semitic cultures go, I’m pretty confident."
And so Semitic cultures attributed diseases to demons. What about Greek thought? I checked my Oxford Classical Dictionary on that, and I found that different people said different things. In the article "healing gods," I learned that the Greeks held that possession (usually by a god) caused certain diseases, particularly epilepsy. Yet, in the article on "medicine," I read that "Hippocratic doctors, by and large, were committed to the idea that the phenomena of health and disease are explicable in the same way as other natural phenomena." In the ancient world, there was the belief that demons caused disease, as well as people who sought natural explanations for it.
As far as Jewish religion is concerned, the Jews had physicians, which may indicate that they saw many diseases as naturally-caused (since they believed in solutions other than exorcism). Jesus Ben Sira was a second century B.C.E. author whose book appears in the Apocrypha, and he praises doctors as agents of God (Sirach 38:1-15) The woman healed from hemorrhages after she touched Jesus' robe consulted physicians in Judea before her encounter with Jesus (Mark 5:26; Luke 8:43). And even the Hebrew Bible can be pretty positive about medicine. Jeremiah 8:22 says, after all, "Is there no balm in Gilead? Is there no physician there?"
But, at the same time, the Jews believed in demons. Jesus referred to Pharisaic exorcists, after all (Matthew 12:27; Luke 11:19).
Of course, blaming disease on demons can lead to tragedy. I've read of Christians who have pursued exorcism instead of medicine to cure disease, with fatal results. And, unfortunately, there have been times when exorcism itself has proven deadly. Once, for example, an exorcist jumped on a sick child's chest to get a demon out of her, resulting in the child's death.
But there may not be a conflict between blaming disease on demons and using medicine to cure it, at least not always. Having a disease does not necessarily mean that one is possessed, since a demon can cause illness without taking residence within the person. Satan caused Job's illness, but he did not possess him. And a demon can use natural causes to bring about disease, as God can utilize secondary causes to effect his will. Therefore, one can use medicine to cure diseases that demons may have brought about.
Can we say that demons are responsible for all disease? Not really. We bring some diseases on ourselves. If I eat poorly and neglect exercise, then I'm susceptible to heart disease. I'll probably get lung cancer if I smoke. Demons don't cause these things. I do (or I would, if I did them).
Yet, Matthew 10:1 says that authority over demons allowed the disciples to heal all manners of diseases. The passage seems pretty comprehensive in attributing disease to demons. Maybe it makes that claim because it doesn't know every natural cause of illness (a liberal view). Or, from a conservative perspective, perhaps demons can cause every disease, but not every person with a disease has it because of demons. A demon can give heart disease to someone who eats right and exercises. But not everyone with heart disease can blame demons, especially when that person eats fatty foods and doesn't get out of the house.
And so Satan is someone who brings disease. God, however, is a healer. Tomorrow, I'll write more about the implications of this.