The most common word in the NT for church is ecclesia. It simply means the “called out ones.” Another word for NT Christians is koninia. It is translated “fellowship, partnership and communion”. Conversion in the NT was marked by the ecclesia becoming a vital part of the koninia. To say it concisely, we were “called out” of the world to be a part of an intimate fellowship, the communion of working partners. We were called to be partners with others in mission. We are called to move from the edge to the inner circle.
“ Those who believed what Peter said were baptized and added to the church that day—about 3,000 in all. All the believers devoted themselves to the apostles’ teaching, and to fellowship, and to sharing in meals (including the Lord’s Supper), and to prayer.” Acts 2:41-42 (NLT)