What sort of peace is it that Jesus asks them to pronounce upon entering each house? And what kind of peace is it of which the angels sing, “Glory to God in the highest and on earth peace”? And if Jesus came not to bring peace, why did all the prophets publish peace as good news? Because this more than anything is peace: when the disease is removed. This is peace: when the cancer is cut away. Only with such radical surgery is it possible for heaven to be reunited to earth. Only in this way does the physician preserve the healthy tissue of the body. The incurable part must be amputated. Only in this way does the military commander preserve the peace: by cutting off those in rebellion. Thus it was also in the case of the tower of Babel, that their evil peace was ended by their good discord. Peace, therefore, was accomplished.
The Gospel of Matthew, Homily, St. John Chrysostom