ON THE PASCH. I. Most writers have wished to expound the mystery of the Pasch by the reckoning of the calculation in the month, the moon, and the day; but, whether through inability of knowledge or of speech, they left it rather obscure, as if they had said nothing about it. For I know that many are accustomed to ask rather scrupulously why, after the manner of the Jews, we celebrate the Pasch with reference to the reckoning of the moon in differing ways, saying that it seems to them more correct, if the commemoration of the Lord's passion is observed, that we should keep a single anniversary day of its occurrence, just as until not long ago it was maintained by very many Gallican bishops, so that they always celebrated the day of the Pasch on the eighth of the Kalends of April, on which the resurrection of Christ is reported to have taken place.
Yet it pleased me, since I have inquired curiously into what our forefathers followed, to set it forth openly. II. The passion of Christ is the redemption of creation, for which the day and the moon were to come together. Nor indeed is this without the authority of Scripture. For Moses says: 'This month shall be for you the beginning of months: it shall be the first in the months of the year' (Exod. 12:2). By which word he consecrated the whole month to the day of the world's birth. So our forefathers, who found the world's birthday on the eleventh of the Kalends of April, establishing it as the first month, fixed it on the eleventh of the Kalends of May. Thus it will be permitted to celebrate the Pasch neither before the eleventh of the Kalends of April nor after the eleventh of the Kalends of May. But when in this month both the moon and the day had come together — namely the fourteenth moon and the Lord's day — then the Pasch was to be celebrated.
Indeed, because again the fourteenth moon often coincides with the Lord's day, they preferred to extend the moon by seven days, provided they retained the Lord's day in the joy of the resurrection. So when the day comes thus up to the twenty-first moon, on account of the Lord's day we always defer the Pasch, so that it is celebrated neither before the eleventh of the Kalends of April nor after the eleventh of the Kalends of May: thus it was found that the month and the day and the moon should be retained in the celebration of the Pasch. VII. Prudently therefore we shall be brought back rather to the moon and the day than to the eleventh of the Kalends of April, to the world's birthday. For the moon at its first quarter lights up all the darkness of night, and the Lord's day is the resurrection of days: for it has returned to the beginning, and renews the faith of days.
These things are rather to be observed in the joy of the world's birth and in the liberation of creation, especially when they are kept within the bounds of the first month. Again, they gave a greater religious regard to the day than to the moon. For we pass beyond the fourteenth moon; but the day we never pass beyond, because all salvation is in the resurrection of the day. Now the Lord's day has both the beginning of days and the resurrection; on account of which the Lord rose again on it; but the moon, although extended even to the twenty-first part, does not fill the whole night: yet it lights up most of the night, and behind itself indeed it leaves darkness, but that which is ahead of it, it overcomes.
In this matter our forefathers preferred that the Pasch should be celebrated up to the twenty-first rather than before the fourteenth. Because to leave the darkness behind one's back is better than not to be able to overcome the darkness lying ahead. And so, by this summary and this conclusion which was established by our forefathers, the Pasch can be celebrated neither before the eleventh of the Kalends of April nor after the eleventh of the Kalends of May. What the reason for establishing this limit was, so far as our slender ability could reach, we have declared: through the grace of our Saviour Jesus Christ, to whom be honour and glory through the ages, and unto the ages of ages. Amen.