Also called the Christian Year, the Church Year is the original catechism of the people of God first given by God to Moses for Israel. Its purpose is not merely to mark past dates and remember them in some kind of sentimental way, but to provide a rhythm for living by which we reenact those events in the Liturgy of the sanctuary and in the liturgy of life in order to actually participate in these events, entering into them as a present, living and transforming experience. In the Church Year, we do not merely remember the Exodus; we experience it. We do not merely remember that Jesus broke bread and drank wine with his disciples on some night long ago; we actually sit at His Table and eat and drink with Him. This type of participation in the reality of the events marked by the Church Year is the biblical idea of “remembrance.” When Jesus says, “Do this in remembrance of Me,” He is talking about the covenantal kind of remembrance that enters into an experiential, actual, metaphysical relationship and union with what is being remembered. Such remembrance is not that of mere scribes who only describe events in chronological time. Rather, it is the kind of remembrance that participates in the events remembered and that relates to the people remembered in karios time, which is that form of time and space by which we access any time and place in the power of the Holy Spirit. The Church Year is therefore the framework of our remembrance.
Also see Catechism, Liturgy, “Our Journey Through the Church Year,” and Seasons.