"And he is the head of the body, the church." (Colossians 1:18)
I want to ask and answer and explore one very simple question: what happens when a body part is severed from the rest of the body and subsequently from its head?
The obvious answer is that it dies. If I were to cut off a finger today it would die, it would certainly not be able to move on its own, sustain its own life, or prevent the decaying of the flesh.
So, what happens when a person chooses to separate from the body of Christ, his church? If the metaphor holds up then the answer is the same, death. Apart from a connection to the body a member of the body will cease to live. So it holds true with members of the church. A member of the church who is cut off from the church will cease to live.
What are some ways that a person may be cut off from the church and from Christ?
The first way, and the most common way in my context, is to voluntarily disassociate with the body of Christ in the local context. Many people claim Christ, claim to be students of the Scriptures, claim to pray, and yet do not worship with the church. They are "spiritual" and spiritually isolated at the same time. Hebrews warns us against such behavior, "Let us not give up meeting together, as some are in the habit of doing, but let
us encourage one another--and all the more as you see the Day approaching." Separation from the body leads to death. Separation from Christ's body leads to separation from Christ and spiritual death. If you have separated from the church it is time to repent and be reunited with Christ through his body. (Hebrews 10:25)
The second way to be cut off from Christ and his church is through theological heresy. In Colossians two Paul deals with this very thing. Paul is contesting the claims of false teachers who are trying to blend superstition with Jewish practices and Christ to form some sort of hybrid super religion. But, Paul says, in reality they are cut off from Christ the head. "He has lost connection with the Head, from whom the whole body, supported and held together by its ligaments and sinews, grows as God causes it to grow." (v.19) They jettisoned the gospel in favor of tradition and superstitions. Today many people jettison the gospel for all kinds of reasons. Be sure that the biblical Christ is always at the forefront of your faith.
How can you remain connected to the body and connected to Christ? Become and remain a member of a faithful, bible believing, Christ exalting, gospel loving, theologically rich congregation. Make sure your pastor hasn't jettisoned core components of the Christian faith (think of the Apostles Creed or justification by faith) and make sure that you remain firmly connected to the body through worship, prayer, and fellowship with the saints.