But because it is now our intention to discuss the visible church, let us learn even from the simple title “mother” how useful, indeed how necessary, it is that we should know her. For there is no other way to enter into life unless this mother conceive us in her womb, give us birth, nourish us at her breast, and lastly, unless she keep us under her care and guidance until, putting off mortal flesh we become like the angels. Our weakness does not allow us to be dismissed from her school until we have been pupils all our lives.
John Calvin, The Institutes of Christian Religion, trans. John McNeil, p. 1016.