Do not long for division, but rather bring those who contend to peace. Judge righteously, and do not respect persons in reproving for transgressions. You shall not be undecided whether or not it shall be. Didache (A.D. 80-140) ch. 4

Every kind of faction and schism was abominable in your sight. You mourned over the transgressions of your neighbors: their deficiencies you deemed your own. Clement of Rome (A.D. 96) ch. 2

Every kind of honor and happiness was bestowed upon you, and then was fulfilled that which is written, “My beloved did eat and drink, and was enlarged and became fat, and kicked.” Hence flowed emulation and envy, strife and sedition, persecution and disorder, war and captivity. So the worthless rose up against the honored, those of no reputation against such as were renowned, the foolish against the wise, the young against those advanced in years. Clement of Rome (A.D. 96) ch. 3

Wherefore are there strifes and wraths and factions and divisions and war among you? Have we not one God and one Christ and one Spirit of grace that was shed upon us? And is there not one calling in Christ? Wherefore do we tear and rend asunder the members of Christ, and stir up factions against our own body, and reach such a pitch of folly, as to forget that we are members one of another? Remember the words of Jesus our Lord: for He said, Woe unto that man. It were good for him if he had not been born, rather than that he should offend one of Mine elect. It were better for him that a mill-stone were about him, and he cast into the sea, than that he should pervert one of Mine elect. Your division has perverted many; it has brought many to despair, many to doubting, and all of us to sorrow. And your sedition still continues. Clement of Rome (A.D. 96) ch. 46

Who therefore is noble among you? Who is compassionate? Who is fulfilled with love? Let him say; If by reason of me there be faction and strife and divisions, I retire, I depart, whither you will, and I do that which is ordered by the people: only let the flock of Christ be at peace with its duly appointed presbyters. Clement of Rome (A.D. 96) ch.54

As children therefore [of the light] of the truth, shun division and wrong doctrines; and where the shepherd is, there follow you as sheep. For many specious wolves with baneful delights lead captive the runners in God's race; but, where you are at one, they will find no place. Ignatius: to the Philadelphians (A.D. 35-105) ch.2

Abstain from noxious herbs, which are not the husbandry of Jesus Christ, because they are not the planting of the Father. Not that I have found division among you, but filtering. Ignatius: to the Philadelphians (A.D. 35-105) ch.3

He shall also judge those who give rise to schisms, who are destitute of the love of God, and who look to their own special advantage rather than to the unity of the Church; and who for trifling reasons, or any kind of reason which occurs to them, cut in pieces and divide the great and glorious body of Christ, and so far as in them lies, [positively] destroy it,-men who prate of peace while they give rise to war, and do in truth strain out a gnat, but swallow a camel. Irenaeus (A.D. 180) Ante-Nicene Fathers vol.1 pg. 508