I was thinking this morning while driving to work about why some churches grow and others don't. I know that there are a number of "growth factors" to consider, which can be addressed by a church that desires to grow. But, in my heart, I think that there are really only two reasons why a particular church would grow.
1) God wills it.
I really believe that many churches have seasons of numeric growth because in God's sovereignty, he pours out his Spirit and moves the hearts of people toward unity and mission. Of all the factors that pertain, God's will has got to be the thing that pulls them all together.
2) The people are passionate about bringing others to Christ.
Personally, I believe that any local church could grow if the people believe deep down in their bones that there are the eternal destinies of others at stake, and they are willing to do whatever it takes to see those others come to Christ. If bringing pre-Christians to Christ is the organizing and driving force through which all activity is filtered, there will be great flexibility in how that's carried out.
NOTE: When I say "the people," the pastor is included.