In Catholicism, the magisterium is the authority that lays down what is the authentic teaching of the Church. For the Catholic Church, that authority is vested uniquely in the pope and the bishops who are in communion with him.[3] Sacred Scripture and Tradition "make up a single sacred deposit of the Word of God, which is entrusted to the Church",[4] and the magisterium is not independent of this, since "all that it proposes for belief as being divinely revealed is derived from this single deposit of faith."[5]
Solemn and ordinary
The exercise of the Church's magisterium is sometimes, but only rarely, expressed in the solemn form of an ex cathedra papal declaration, "when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, [the Bishop of Rome] defines a doctrine concerning faith or morals to be held by the whole Church",[6] or of a similar declaration by an ecumenical council. Such solemn declarations of the Church's teaching involve the infallibility of the Church.
Pope Pius IX's definition of the Immaculate Conception of Mary, and Pope Pius XII's definition of the Assumption of Mary are examples of such solemn papal pronouncements. Examples of solemn declarations by ecumenical councils are the Council of Trent's decree on justification, and the First Vatican Council's definition of papal infallibility.
The Church's magisterium is exercised without this solemnity in statements by popes and bishops, whether collectively (as by an episcopal conference) or singly, in written documents such as catechisms, encyclicals and pastoral letters, or orally, as in homilies. These statements are part of the ordinary magisterium of the Church.
The First Vatican Council declared that "all those things are to be believed with divine and Catholic faith which are contained in the Word of God, written or handed down, and which the Church, either by a solemn judgment or by her ordinary and