This text below is taken from Mark Dever's book What is a Healthy Church? When churches don't teach the Bible and sound doctrine they become unhealthy.
What does an unhealthy church look like? It's a church where the sermons often veer into cliche and repetition. Worse yet, they become moralistic and me-centered, and the gospel is recast as little more than spiritual "self help". Conversion is viewed as an act of human resolve. And by varying degrees, from bad to worse, the culture of the church is indistinguishable from the secular culture surrounding it.
The church is not a place. It's not a building. It's not a preaching point. It's not a spiritual service provider. It's a people - the new covenant, blood- bought people of God. That's why Paul said, "Christ loved the church and gave Himself up for her" (Ephesians 5:25). He didn't give himself for a place, but for a people.
I pray that pastors would increasingly recognize their awesome responsibility for the particular flocks over which God has made them under-shepherds.
But I also pray that Christians, whether an elder or an infant in the faith, would increasingly 
recognize your responsibility to love, serve, encourage, and hold accountable the rest of your church family. When it comes to your flesh-and-blood siblings, I trust you already recognize where Cain went wrong when he dismissively said to the Lord, "Am I my brother's keeper?" But even more I hope that you recognize, if you haven't already, your higher responsibility to the brothers and sisters of your church family.
recognize your responsibility to love, serve, encourage, and hold accountable the rest of your church family. When it comes to your flesh-and-blood siblings, I trust you already recognize where Cain went wrong when he dismissively said to the Lord, "Am I my brother's keeper?" But even more I hope that you recognize, if you haven't already, your higher responsibility to the brothers and sisters of your church family. What is a Healthy Church?, pp. 34, 38, & 89.
