John Chrysostom — as excerpted in the Catena Aurea on Matthew 10:34-36

“(Hom. xxxv.) How then did He enjoin them, that when they should entor any house they should say, Peace be to this house, as also the Angels sung, Glory to God in the highest, on earth peace to men. (Luke 2:14.) That is the most perfect peace when that which is diseased is lopped off, when that which introduces strife is taken away, for so only is it possible that heaven should be joined to earth. For so does the physician save the rest of the body, namely by cutting off that which cannot be healed. So it came to pass at the tower of Babel; a happy discord broke up their bad union. So also Paul divided those who were conspired together against him. For concord is not in all cases good; for there is honour among thieves. And this combat is not of His setting before them, but of the plots of the world.”