834 Particular Churches are fully catholic through their communion with one of them, the Church of Rome "which presides in charity."315 "For with this church, by reason of its pre-eminence, the whole Church, that is the faithful everywhere, must necessarily be in accord."316 Indeed, "from the incarnate Word’s descent to us, all Christian churches everywhere have held and hold the great Church that is here [at Rome] to be their only basis and foundation since, according to the Savior’s promise, the gates of hell have never prevailed against her."317
835 "Let us be very careful not to conceive of the universal Church as the simple sum, or . . . the more or less anomalous federation of essentially different particular churches. In the mind of the Lord the Church is universal by vocation and mission, but when she put down her roots in a variety of cultural, social, and human terrains, she takes on different external expressions and appearances in each part of the world."318 The rich variety of ecclesiastical disciplines, liturgical rites, and theological and spiritual heritages proper to the local churches "unified in a common effort, shows all the more resplendently the catholicity of the undivided Church."319