If People Are Against You, You Must Be Doing a Good Job?

I recently heard the following sentiment expressed by a church pastor: if a church is being effective in its service and ministry, then a pastor can expect that a certain number of people within the church body will be unhappy. Why? Because Satan seeks to attack healthy, vibrant churches so he can cause a spirit of bitterness to take root from within. Satan doesn't attack ineffective churches because, basically, there's no bang for the buck. He further explained that this is a common reason why churches fail, because, I guess, they are so effective that people are very unhappy.

This idea was expressed to a group of church leaders gathered for an official meeting. So the message was, in effect: if we're doing our job, you can expect some of your fellow church members to become bitter and divisive. This is to be expected but do not fear! Move ahead because that just means we're doing a really good job. (He did also suggest that they guard themselves against a spirit of bitterness....which is good)

So I'm just wondering. Does this sound right to you?

It's sort of my feeling that while Satan definitely can and does attack effective churches, and while it's also true that sometimes people in effective churches can become unhappy for a variety of reasons (you can't please all the people all the time, right?), that it makes more sense that Satan would attack a church from the outside, rather than from the inside. At least as a general rule.

I am also of the belief that, scripturally speaking, this whole idea doesn't really jive with what I have read in scripture. I thought believers were of one body and were supposed to love each other and get along. I thought we were supposed to make every attempt to settle our differences, by approaching each other in humility and love and we are to be open to loving correction. Aren't we accountable each to the other?

Does Satan use Believers to attack effective churches from within? Your thoughts?