3 For there are other mountains which cause shipwreck, on which, if any one drive his ship, she is dashed to pieces. For it is easy, when land is seen by men in peril, to make a venture as it were to reach it; but sometimes land is seen on a mountain, and rocks lie hidden under the mountain; and when any one makes for the mountain, he falls on the rocks, and finds there not rest, but wrecking. So there have been certain mountains, and great have they appeared among men, and they have created heresies and schisms, and have divided the Church of God; but those who divided the Church of God were not those mountains concerning which it is said, “Let the mountains receive peace for your people.” For in what manner have they received peace who have severed unity?
Source: Tractates on the Gospel of John (New Advent)