From The New Scroll (Novaya Skryzhal), by Archbishop Benjamim Krasnopevkov-Rumovsky (1798–1811), on the Dormition Fast.
“The fast in August (Dormition Fast) was established in honor of the Mother of God the Word, Who foreknowing her imminent repose, as she always labored ascetically and fasted for us—even though as holy and All-Pure she had no need of fasting—especially prayed for us when she prepared herself to pass over from this life into the future life, and as her blessed soul made ready through the divine Spirit to be united with her Son. And therefore, we too must fast and sing hymns to her, emulate her life, and thus encourage her to pray for us. Some incidentally say that this fast was instituted in honor of two feasts—the Transfiguration and the Dormition. I likewise consider it necessary to remember both of these feasts—one as granting us illumination, and the other as mercy and intercession for us.”
Thus Balsamon’s answer to Photius’s question testifies that these three fasts—of the Nativity, the Apostles, and the Dormition—although originating at an unknown time and from an unknown tradition, were nevertheless confirmed at one Constantinople Council. For at that council the question was posed: Should we observe the fast in the month of August (the Dormition fast)? And this question was answered. At first the fast was observed at a different time, but later it was transferred, so that this fast would not correspond to the pagan fasts. Moreover many people observe this fast today.
Balsamon gives us an answer to this question and explains: “At one time this was asked at a council under the chairmanship of our sovereign and most august emperor and in the presence of His Holiness Patriarch Kyr Lukas and other archbishops who were located here. Certain people said that the fast should not be observed as a consequence of its transfer (explained above). Others to the contrary insisted that when the holy council speaks clearly that this once was, then we should necessarily observe it, even though it is not known where and at what occasion it was transferred. The patriarch and hierarchs pronounced that the fast must definitely be in the month of August, and as proof of his decision he pointed to the scroll of unification (printed in the Rudder), which obligated men who have been married thrice to receive Communion three times a year—that is, on Pascha, on the Dormition of the Mother of God, and on the Nativity of our Lord Jesus Christ, for these feasts were preceded by fasts, after which this Sacrament was offered. Because at that time doubts also arose concerning the number of days of this fast, which were not indicated anywhere, His Holiness the Patriarch said that although the number of days are not prescribed in any written document for the Dormition fast, or for the fast that is observed before the feast of the Nativity of Christ, we should follow the unwritten Church Tradition and fast from the first day of August and from the fourteenth day of November. Thus was it all considered. But when I myself considered: From whence and in what manner did these two fasts become tradition—that is, the fast of the Dormition of the Theotokos and the fast of the Nativity of Christ our God, so also the fast instituted in honor of the Apostles and the feast of the Transfiguration—then should we also observe these fasts, and for how many days? I came to the following conclusion: The fasts of these four feasts should indisputably be observed. Although the number of days in them differ from that of the Great Forty-Day Fast, nevertheless before these feasts all the faithful, monastics and laity, should definitely fast at least seven days under penalty of excommunication from the community of Orthodox Christians. Monks, being inspired by the rules of their founders, should fast even longer—that is from the feast of All Saints and from the fourteenth day of the month of November [the Apostles’ fast and the Nativity fast respectively]. Those who do not want to follow what was spoken by their founders should be forced to fast, for this is a right and saving work.”