The Shepherds, the Flock, the Church of God

Does the Bible teach that all Christians are to be members of a local church? Does the Bible make allowances for true believers to ignore the local church? Why is the local church so important?

Three Point Sermon:

I. We Must Discern Between the Universal and Local Church.
II. Christians Are People Who Are Required to Be Accountable.
III. Membership: The Means for Sheep and Shepherds to Unite for Christ's Glory.