We say not My Father, but “Our Father,” for the teacher of peace and master of unity would not have men pray singly and severally, since when any prays, he is not to pray for himself only. Our prayer is general and for all, and when we pray, we pray not for one person, but for us all, because we all are one. So also He willed that one should pray for all, according as Himself in one did bear us all.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Tr. vii. 4