When God saves someone from sin and death, he saves them to the family of God. On this side of eternity, believers unite themselves to local church bodies as God intended.
Membership is the formal commitment a Christian makes to belong to a local church. As a member united to the body, one commits to protect the unity of the church, share the responsibilities of the church, serve in the ministries of the church, and support the testimony of the church.
At Anchor Church, we like to say that membership isn't like a contract made to a social club or organization. Membership is the commitment we make to belong to one another in the season God has knit us together for his glory and our good.