Whether we like it or not, the moment we confess Jesus Christ as our Lord and Savior, that is, from the time we become a Christian, we are at the same time a member of the Christian church – even if we do not permit our name to be placed on a church roll, even if we refuse to identify ourselves with a particular congregation and share responsibilities with them, even if we absent ourselves from the worship of a congregation. Our membership in the church is a corollary of our faith in Christ. We can no more be a Christian and have nothing to do with the church than we can be a person and not be in a family. Membership in the church is a basic spiritual fact for those who confess Christ as Lord. It is not an option for those Christians who happen by nature to be more gregarious than others. It is part of the fabric of redemption.
There are Christians, of course, who never put their names down on a membership list; there are Christians who refuse to respond to the call to worship each Sunday; there are Christians who say, “I love God but I hate the church.” But they are members all the same, whether they like it or not, whether they acknowledge or not. For God never makes private, secret salvation deals with people. His relationships with us are personal, true; intimate, yes; but private, no. We are a family in Christ. When we become Christians, we are among brothers and sisters in faith. No Christian is an only child.
(Eugene H. Peterson, A Long Obedience in the Same Direction, p.175)