The apostles entrusted the “Sacred deposit” of the faith (the depositum fidei), contained in Sacred Scripture and Tradition, to the whole of the Church. “By adhering to [this heritage] the entire holy people, united to its pastors, remains always faithful to the teaching of the apostles, to the brotherhood, to the breaking of bread and the prayers. So, in maintaining, practising and professing the faith that has been handed on, there should be a remarkable harmony between the bishops and the faithful.”
The Magisterium of the Church
“The task of giving an authentic interpretation of the Word of God, whether in its written form or in the form of Tradition, has been entrusted to the living teaching office of the Church alone. Its authority in this matter is exercised in the name of Jesus Christ.” This means that the task of interpretation has been entrusted to the bishops in communion with the successor of Peter, the Bishop of Rome.
“Yet this Magisterium is not superior to the Word of God, but is its servant. It teaches only what has been handed on to it. At the divine command and with the help of the Holy Spirit, it listens to this devotedly, guards it with dedication and expounds it faithfully. All that it proposes for belief as being divinely revealed is drawn from this single deposit of faith.”
Mindful of Christ’s words to his apostles: “He who hears you, hears me”, The faithful receive with docility the teachings and directives that their pastors give them in different forms.
From the Catechism of the Catholic Church 84-87