Johannes Quasten, Patrology, vol. II: The Ante-Nicene Literature After Irenaeus (Westminster: Christian Classics, 1990) 147, 149.
Quasten discusses the Didascalia, a third century Christian document composed "for a community of Christian converts from paganism in the northern part of Syria" (147):
...the author turns to the danger of heresies...God has left the synagogue and has come to the Church of the Gentiles, but Satan has done the same. He does not tempt the Jews anymore, but he splits the one [Christian] fold into sects (149).
I've often heard Christians say: "You can tell that you're doing something right when things are going wrong! That shows Satan feels threatened and is attacking the move of God."
In The Prayer of Jabez, Bruce Wilkinson discusses a seminary student who is talking with his professor. When the student tells his professor that everything is running smoothly, the professor has a concerned look on his face. "You must not be in the battle," the professor remarks, "for Satan attacks those who are doing God's work."
At DePauw University, an influential Christian group was taking off like a wildfire, as numerous students from a variety of backgrounds came to praise God and hear the Gospel of Jesus Christ. But there were disagreements along the way, and the cultish International Church of Christ was trying to make inroads into our school. Some Christians attributed these things to Satan, who was trying to disrupt the work of God.
The summer that I graduated from DePauw, I attended a small evangelical church in the backwoods. The first night I was there, a debate erupted over whether Christians should keep the Seventh-Day Sabbath. Eventually, the pastor remarked: "Why is it we always get into these divisive arguments? It's Satan, isn't it?"
At Harvard, I was President of an evangelical Christian fellowship group at the Divinity School, and we were organizing a night of praise and worship. On the night of the event, so many things were going wrong! One lady, a pastor, remarked that this was actually a good sign. "When everything's going well, then that's not a good sign," she said. "Satan tries to disrupt what he considers a threat!"
At the same time, Christians also like to attribute good events to the presence of God. A Jehovah's Witness lady once told my family that her church was the only true one because everyone loved one another, worked together to build the new Kingdom Hall, and had no doctrinal divisions. "We all believe the same thing," she said. "Do you know any other churches like that?" But the Didascalia would say that the absence of problems is a bad sign, an indication that Satan doesn't consider the JWs enough of a threat to attack them!
I'm not sure if Christian groups suffer more problems than other people, or if they're just incorporating bad events into a narrative that tries to explain their significance. The Didascalia says that Satan does not tempt the Jews anymore, whereas he seeks to divide Christianity into sects. At the time that the Didascalia was written, Judaism was rather united under the authority of the rabbis. But the Jews still encountered problems: competition from Christianity, the temptations of paganism, later persecution. If problems are an indication of Satanic attacks on God's people, then why can't they assert that Satan is threatened by them?
I don't know where I stand on a lot of this. The body of Christ should take heed of destructive strife within its midst, but I don't think it should suppress disagreement with the usual "Satan causes divisions" line. And problems should encourage us to depend on God, whether Satan is causing them or not. Or at least that's my humble opinion!