Evil is a parasite

I've come to the conclusion that evil always works through people. That's why we need to love our enemies (Matthew 5:44); they are just tools.

Think about it: whenever the Bible talks about demons they are always spirits, lodging themselves in people or animals. These spirits seem to have no material form; they must possess someone else's life to manifest themselves. For example, in the account where Jesus casts a whole group of demons out of one man, the spirits begged to be sent to a herd of pigs (Mark 5:1-20).

There was even one occasion where Jesus rebuked Satan while talking to his disciple Peter (Matthew 16:23). In this instance, Peter was not possessed with the bad spirit, but he uttered thoughts and words that were from Satan and Jesus was none too pleased with him.

How does evil influence us? Thoughts. If we are not careful, these thoughts take root in our being and lead us to commit evil deeds. Jesus resisted the Devil when he was being tempted. Because of Christ's Spirit living inside us, Christians have great power to resist evil influences too.

Moreover, Jesus encourages us to exercise that power not just in our own lives but also on behalf of others who can't resist--this, I think, being the force of His command to pray for our enemies.