The Greek word 'Koinonia' is the word that refers to the deep "fellowship" that the early Christians had together. It is something that many Christians today long for - and it really is the essence of 'church life' in the Bible. But to a very large degree the modern church seems to have lost it.

When we have a 'service' or meeting today, where everyone comes and sits in rows facing the front, sings some songs and listens to the sermon, then says "Bless you" to a few people and goes home - that is far from true 'koinonia'. Even in quite a few cell
groups and house meetings today, there is little deep fellowship.
-It is more like a miniature "church service" - where a few people do all the 'ministry' and the rest sit around and watch.
We need to realize that 'koinonia' was at the very center of the way the early church lived out their lives. Without this, I do not believe that we truly have "church" at all. We may have a 'meeting' but we do not have deep fellowship. And without this, we really have nothing. (Andrew Strom)