I know some people who claim to be Christians but "don't do church", who choose rather to keep their Christianity on their own, to themselves. My assumption is that they haven't actually read the Bible or don't truly believe what they claim to believe. Christ doesn't give us the option to live out a relationship with Him by ourselves; He very clearly states that it is His commandment to us that we love one another and that those who do not obey this command will be tossed into the fire (Jn 15:6). There are certainly times when I wish this were not His command. The introverted side of me would like to join the club of people unattached to other Christians. Where it's easier to hide my feelings, where I'm not responsible for helping others, where personal sin stays personal. Where I don't experience the love of others committed to a relationship with me, where no one confronts me with my sin so I will repent of it, where I'm not encouraged by those struggling with the same things I am and those who have triumphed over those same difficulties. Christ commands us to be active, loving members of His body for our own sake and for the sake of the other members. Not only should we belong to a local group of believers, but we should invest ourselves in them. We should love them as Jesus Christ loves us. We should be so attached that we're willing to lay down our lives for them, figuratively in regular service as well as literally. If we belong to Christ, then we belong to His body, and should remain in Him by loving one another.