Church membership was so important that Paul and Silas baptized the Philippian jailer into the membership of Christ's church at midnight with Paul's back still bloody from a beating! He did not even wait till morning! Identification with Christ's church is important; without it, one must be treated 'as a heathen and publican.'
Handbook of Church Discipline: A Right and Privilege of Every Church Member (ed. HarperCollins Christian Publishing, 2016) - ISBN: 9780310535478