I know many people who have grown up in church that cannot define what a church is. I don't really know that I can. I have a definition that I think is workable although there is a niggling doubt that it is somehow incomplete.
Before I get to my working definition, I think it is important to ask, "Do we need a definition?" Since most people cannot define it does it need definition. Is the understanding sufficiently clear to negate the need for a clearer casting of the term? The reason that there needs to be a clear definition is that it affects how we choose, join and leave our churches. Without a firm biblical idea of what a church is, even the concept of church membership is moot. If a church is merely a chance gathering of Christians then I can come or go as I see fit. Or, if Matthew 18:20 defines a church than I can stay home and have church with my family. It is important to know what terms mean and the word "Church" is no exception.
Another quick digression is the matter of local vs. universal. I realize that there are some who deny the existence of the universal or invisible church. It seems evident from a passage like Ephesians 5:25 that there is some kind of universal body of all who truly believe in Christ and He relates to that body. At the same time there is clearly a need to focus on some kind of local church who is actually able to work together in time and space to edify each other and to evangelize the lost around them. So my question is essentially: "What is a local church?"
I have this definition from the Catechism for Boys and Girls: "A church is an assembly of baptized believers, joined by a covenant of discipline and witness, who meet together regularly under the preaching of the Word of God."
The key points of this answer are crucial. Assembly is the actual Greek term that has come to translated as "church." It emphasizes the community and the need that we have to be in regular conversation and contact with others who are striving to live godly lives. Furthermore, it underlines that while we have a private duty to the Great Commission there is also a corporate responsibility. Baptized: while I am not at all a Big-B-Baptist, the Bible stresses this step of obedience in the life of true believers. To some the placing the word Believers in a definition of church might have seemed ridiculous. But from the Puritan's "Grandfather Clause" to the modern problem of allowing "seekers" to join churches there is a trend by some to allow membership to those who have shown no desire to repent of sin and turn to Christ in faith.
That people should be held or Joined together is a state of nature. People can not be counted on to do what is right or even to act in their own self-interest. One only has to witness a crisis where people will do foolish things instead of banding together for their own safety and the common good. Mankind is in need of accountability to accomplish almost any worthwhile task. This joining is two-fold. First is an agreement for Discipline. Our salvation starts with justification when we are judicially declared righteous in the righteousness of the Lord Jesus Christ. Unfortunately that is only the beginning. It is interesting that it is not Paul, Peter or James who tells us how to confront sin among believers but the Lord Himself in Matthew 18. We need to pursue holiness and we need to encourage it in others and we need to be ready to let others pursue holiness in us. This kind of "iron sharpening iron" sets up the second part of the covenant. Witness is the feet of the Gospel. The Church as a corporation can not witness without the individual lives of the members. The members can witness so much more effectively when it is not just their story but a multitude of witnesses all saying to the world, "Repent for the Kingdom of God is at hand!"
And all this is accomplished by the regular Meeting of God's people to encourage each other to discipline themselves to holiness and to spread the Gospel. As they sit under the regular Preaching of the Bible they are built up and equipped to allow the Holy Spirit to fill them with the mind of Christ and to go out into the world to tell others the good news!
I hope that this gets you thinking about what your view of Church is. In part 2 we will look at how this should impact our church life and, we will look at practical implications of this viewpoint. It is important to know what we are talking about. Everything we believe about church membership, church purpose and methodology is based on what we believe a church really is.
So, now you have my definition. What is yours?