Irenaeus of Lyons, Against Heresies 4.33.7-8
Consider also those who create schisms. They are hollow, lacking the love of God, and they weigh their own advantage more heavily than the unity of the Church. Over trifling and arbitrary causes they tear apart the great and glorious body of Christ, and insofar as they are able, they kill it. They speak of peace but wage war, truly straining out a gnat while swallowing a camel. No correction they might offer can ever match the destruction that schism brings. He will judge all who stand outside the truth — that is, outside the Church — yet He Himself will be judged by no one. All things hold fast for Him: complete faith in one God Almighty, from whom all things come; faith in the Son of God, Christ Jesus our Lord, through whom all things exist; and a firm conviction, rooted in the Spirit of God, concerning His dispensations, by which humanity was made the Son of God. This Spirit supplies the knowledge of truth and has unfolded the dispensations of the Father and the Son, according to which He drew near to the human race, just as the Father willed.
Latin
1. Jupicasnrr autem et eos qui schismata operantur, qui sunt inanes, non habentes Dei dilectionem, suamque utilitatem potius considerantes quam unitatem Ecclesiz : et propter modicas et quaslibet causas magnum et gloriosum corpus Christi conscindunt et dividunt, et quantum in ipsis est, interficiunt: pacem loquentes et bellum operantes: vere liquantes culicem et cametransglutientes. Nulla enim ab eis tanta potest fieri correctio, quanta est schismatis pernicies. Judicabit autem et omnes eos qui sunt extra veritatem, id est qui sunt extra Ecclesiam: ipse autem a nemine judicabitur. Omnia enim ei constant: et in unum Deum omnipotentem, ex quo omnia, fides integra; et in nat eis +O Filium Dei Christum Jesum Dominum nostrum, per quem omnia, — et dispositiones ejus, per quas homo factus est Filius Dei, sententia firma, quze est in Spiritu Dei, qui preestat agnitionem veritatis, qui dispositiones Patris et Filii exposuit, secundum quas aderat generi humano, quemadmodum vult Pater.