Because the church cares. Because this is how the Spirit, through this Church on earth, leads us to shape our lives. Not according to the events of the day or the events that others have determined are the events of the day, or even according to what another individual – your favorite spiritual writer, the Spiritual Flavor of the Month or even the most serious Catholic in the World – tells you.
First comes the .shape of the liturgical year. That is the center of our prayer. The prayers that the Holy Spirit, through the Church gives us.
Paul says, “We do not know how to pray as we ought.” And in that context (Romans 8:26), he says that the Spirit helps us in that very weakness.
And how? In many ways, but fundamentally, at root, through the warp and woof of this Church that the Spirit breathed into life on Pentecost. If we do not know how to pray as we ought, we begin with the prayer of the Church – the liturgical year, the Office, the Mass.
I once was part of a spiritual experience that included daily morning and evening prayer for a few days. What surprised me about this Catholic experience was that the shape of the prayer was determined by the leader who, guitar in hand, decided what Scriptures would be the focus of the group’s twice-daily prayer, what music would be sung and what other prayers would be said. This daily prayer of this Catholic experience never had any reference to the daily Mass readings or any saints or feasts of the day, much less any of the prayers from the liturgy of the Hours. It was all very sincere, but the understanding of “Spirit-led” struck me as repetitive, lacking in depth or connection to the richness of Catholic spirituality, and far too dependent on one individual’s will.
Anyway, don’t think I am suggesting you read the Office everyday. It’s just a good thing to know about, I say Prime in the morning and sometimes I say Compline at night but usually I don’t. But anyway I like parts of my prayers to stay the same and part to change. So many prayer books are awful, but if you stick with the liturgy, you are safe.