Pope Nicholas I, Letter to the Bulgars, 67.

Pope Nicholas I, Letter to the Bulgars, 67.

Written c. 866 CE.

Source: The Responses of Pope Nicholas I to the Questions of the Bulgars A.D. 866 (Letter 99). Trans.: William L. North. Fordham University: Internet History Sourcebooks. 1998. Available online at: https://sourcebooks.fordham.edu/basis/866nicholas-bulgar.asp

Chapter LXVII.

You say that you had a custom that whenever you decided to oblige someone for some matter by swearing an oath, you brought a sword into the center of the gathering and swore an oath by it. Now however, you ask to be instructed by us on what thing you should swear by. We, however, consider it completely unfitting to swear not only by a sword but by any other man-made object. For by whomever someone swears, so, too, does he love and venerate this person and commends his trust to him with firm stability. Therefore, one should swear by God, Whom people should love and venerate, in Whom all hope and trust should be placed, and from Whom all creatures should always expect aid. For when the Lord commands someone not to swear by heaven, earth, one's head or Jerusalem, nothing else is forbidden except to swear by something created. But that we are ordered to swear by the name of God, we learn from Him teaching us. Clearly we can swear at least by those created things which have been assigned to the divine cult, i.e. the temple and the altar, and someone who swears upon them, also swears upon the very people who live in them, if there are any such things there. Therefore, one should rightly swear by the Gospel, for whatever is contained therein is clearly recognized to be no one's if not God's, Who is written and read to be in it. This, indeed, is our law, this our testament, which the Lord our savior, bearer of the law and maker of the will, has assigned to His elect, and if we love it, we also swear by it; for everyone who speaks the truth swears by the one whom he loves. Therefore, if we swear by the Gospel, we are proven to love both the testator and the testament itself and we indicate beyond all doubt that we do not wish to depart from His commandments.