The Bible teaches that membership in a local church is the normal expectation for a healthy Christian. There are exceptions to this general rule (such as missionaries), but that is precisely the point: they are exceptions. Even missionaries in the New Testament seem to have strong relationships with their sending churches. For example, the Apostle Paul had a strong relationship with his supporting church, Philippi. The point is this: sheep (a term the Scriptures often use to describe Christians) are meant to be in a sheepfold. We are meant to be together laboring to bring glory to God.
Christians are called to assemble together regularly to build one another up in Christ (Hebrews 10:23–25), to encourage one another regularly (Hebrews 3:12–14), to work together to get the gospel to lost people around the world (Matthew 28:18–20), to protect each other from sin (James 5:19–20), to guard the church from hypocrisy (Matthew 18:15–18), and to be built up by the regular teaching of God’s Word through gifted teachers (Hebrews 13:17). To faithfully follow these commands, Christians lock arms with other believers in a local assembly to foster deep, authentic, God-glorifying, sin-fighting relationships.
For God’s glory and the good of your soul, First Baptist Church encourages all Christians to partner with a local church in membership.
So, do not merely attend a church (though you should attend), but join a church. Link arms with other Christians. Find a church you can join, and do it so that non-Christians will hear and see the Gospel, so that weak Christians will be cared for, so that strong Christians will channel their energies in a good way, so that church leaders will be encouraged and helped, so that God will be glorified” (Mark Dever, Nine Marks of a Healthy Church, 162–164).