The Epistles of Cyprian

⁵ And therefore the Lord, suggesting to us a unity that comes from divine authority, lays it down, saying, “I and my Father are one.” To which unity reducing His Church, He says again, “And there shall be one flock, and one shepherd.” But if the flock is one, how can he be numbered among the flock who is not in the number of the flock? Or how can he be esteemed a pastor, who—while the true shepherd remains and presides over the Church of God by successive ordination—succeeding to no one, and beginning from himself, becomes a stranger and a profane person, an enemy of the Lord's peace and of the divine unity, not dwelling in the house of God, that is, in the Church of God, in which none dwell except they are of one heart and one mind, since the Holy Spirit speaks in the Psalms, and says, “It is God who makes men to dwell of one mind in a house.”