There are many misconceptions today about many areas of Christianity. There is even a movement among some Christian groups away from a “formal” church membership. The New Testament never mentions the term (in any translation I am familiar with) “church member”, but the attitude with which Paul writes to the various churches and to Timothy reflect what most would see as an implication that there is some form of accountability and “order” to the local “body of believers”. Further, how can effective and real church discipline be carried out without some form of “formal” membership or fellowship?
So why be a “church member”? The first reason might very well be as a testimony and commitment to the work of the local church and to glorifying God through (in/by) the church (Ephesians 3:23). Even of more eternal importance: “The Church” is the Bride of Christ as depicted in Ephesians 5 and Revelation 19.
But there is a cost to “church membership”. The price isn’t in money – but in a willingness to give others permission to help you to remain accountable, to grown, and to serve in God-glorifying ways. But there is another cost – an that of commitment – commitment to walk in Christ as a living testimony of saving faith and total reliance on Christ Jesus.