Catechism Question #81 (April)

Q. What is the duty of such as are rightly baptized?
A. It is the duty of such as are rightly baptized, to give up themselves to some particular and orderly Church of Jesus Christ, that they may walk in all the commandments and ordinances of the Lord blameless.

Acts 2:47b - And the Lord added to the church daily those who were being saved.