What is the Church
This oneness of all the churches does not just come into being a posteriori by the establishment of a creed, a church order, and a synodical system. Neither is the church an association of individual persons who first became believers apart from the church and subsequently united themselves. But it is an organism in which the whole exists prior to the parts; its unity precedes the plurality of local churches and rests in Christ.
Herman Bavinck, Reformed Dogmatics: Holy Spirit, Church, and New Creation, ed. John Bolt, trans. John Vriend, vol. 4 (Grand Rapids, MI: Baker Academic, 2008), 280