40 The Church, like every family, passes on to her children the whole store of her memories. But how does this come about in a way that nothing is lost, but rather everything in the patrimony of faith comes to be more deeply understood? It is through the apostolic Tradition preserved in the Church with the assistance of the Holy Spirit that we enjoy a living contact with the foundational memory. What was handed down by the apostles — as the Second Vatican Council states — "comprises everything that serves to make the people of God live their lives in holiness and increase their faith. In this way the Church, in her doctrine, life and worship, perpetuates and transmits to every generation all that she herself is, all that she believes". Faith, in fact, needs a setting in which it can be witnessed to and communicated, a means which is suitable and proportionate to what is communicated. For transmitting a purely doctrinal content, an idea might suffice, or perhaps a book, or the repetition of a spoken message. But what is communicated in the Church, what is handed down in her living Tradition, is the new light born of an encounter with the true God, a light which touches us at the core of our being and engages our minds, wills and emotions, opening us to relationships lived in communion. There is a special means for passing down this fullness, a means capable of engaging the entire person, body and spirit, interior life and relationships with others. It is the sacraments, celebrated in the Church’s liturgy. The sacraments communicate an incarnate memory, linked to the times and places of our lives, linked to all our senses; in them the whole person is engaged as a member of a living subject and part of a network of communitarian relationships. While the sacraments are indeed sacraments of faith, it can also be said that faith itself possesses a sacramental structure. The awakening of faith is linked to the dawning of a new sacramental sense in our lives as human beings and as Christians, in which visible and material realities are seen to point beyond themselves to the mystery of the eternal.
Source: Lumen Fidei (Vatican.va)