St John Chrysostom on schism

From a homily given by St. John Chrysostom on Ephesians 4:4-7 ("There is one body, and one Spirit, even as also you were called in one hope of your calling; one Lord, one faith, one baptism, one God and Father of all, who is over all, and through all, and in all. But unto each one of us was the grace given according to the measure of the gift of Christ"). Source: https://www.newadvent.org/fathers/230111.htm

For there are two kinds of separation from the body of the Church; the one, when we wax cold in love, the other, when we dare commit things unworthy of our belonging to that body; for in either way we cut ourselves off from the fullness of Christ. But if we are appointed to build up others also, what shall not be done to them who are first to make division? Nothing will so avail to divide the Church as love of power. Nothing so provokes God's anger as the division of the Church. Yea, though we have achieved ten thousand glorious acts, yet shall we, if we cut to pieces the fullness of the Church, suffer punishment no less sore than they who mangled His body. [...] This injury is not less than that received at the hands of enemies, nay, it is far greater. For that indeed renders her even more glorious, whereas this, when she is warred upon by her own children, disgraces her even before her enemies. Because it seems to them a great mark of hypocrisy, that those who have been born in her, and nurtured in her bosom, and have learned perfectly her secrets, that these should of a sudden change, and do her enemies' work.

I mean these remarks for those who give themselves up indiscriminately to the men who are dividing the Church. For if on the one hand those men have doctrines also contrary to ours, then on that account further it is not right to mix with them: if, on the other hand, they hold the same opinions, the reason for not mixing with them is greater still. And why so? Because then the disease is from lust of authority. Do you not know what was the fate of Korah, Dathan, and Abiram? (Numbers 16:1-35) Of them only did I say? Was it not also of them that were with them? What will you say? Shall it be said, Their faith is the same, they are orthodox as well as we? If so, why then are they not with us? There is one Lord, one faith, one baptism. If their cause is right, then is ours wrong; if ours is right, then is theirs wrong. Children, says he, tossed to and fro, and carried about with every wind. [...] How shall we bear the ridicule of the Greeks? For if they reproach us on account of our heresies, what will they not say of these things? If they have the same doctrines, if the same mysteries, wherefore does a ruler in one Church invade another? See ye, say they, how all things among the Christians are full of vainglory? And there is an ambition among them, and hypocrisy. Strip them, say they, of their numbers, and they are nothing. Cut out the disease, the corrupt multitude. Would you have me tell what they say of our city, how they accuse us on the score of our easy compliances? Any one, say they, that chooses may find followers, and would never be at a loss for them. Oh, what a sneer is that, what a disgrace are these things! And yet the sneer is one thing, the disgrace is another. [...] Therefore I assert and protest, that to make a schism in the Church is no less an evil than to fall into heresy. Tell me, suppose a subject of some king, though he did not join himself to another king, nor give himself to any other, yet should take and keep hold of his king's royal purple, and should tear it all from its clasp, and rend it into many shreds; would he suffer less punishment than those who join themselves to the service of another? And what, if withal he were to seize the king himself by the throat and slay him, and tear his body limb from limb, what punishment could he undergo, that should be equal to his deserts? Now if in doing this toward a king, his fellow-servant, he would be committing an act too great for any punishment to reach; of what hell shall not he be worthy who slays Christ, and plucks Him limb from limb?