27.
Both the authority of the Divine Scriptures and the consent of the whole Church spread throughout the world have combined to ordain the annual commemoration of these things at Easter, by observances which are, as you now see, full of spiritual significance. From the Old Testament Scriptures we are not taught as to the precise day of holding Easter, beyond the limitation to the period between the 14th and 21st days of the first month; but because we know from the Gospel beyond doubt which days of the week were signalized in succession by the Lord's crucifixion, His resting in the grave, and His resurrection, the observance of these days has been enjoined in addition by Councils of the Fathers, and the whole Christian world has arrived unanimously at the persuasion that this is the proper mode of observing Easter.