The Church and its Ministry

What does the Church do?
How does the Church proclaim Christ and confess truth at the same time?
What is the derivation of the Church’s public ministry?
Are there primary and secondary tasks in the Church’s ministry?
How is the individual service of a Christian different from his/her participation in the public ministry? How are we to regard the public ministry of churches that adhere to wrong teachings?
Is the ministry of churches that mix truth and error efficacious?