The Magisterium of the Catholic Church

Defined as "the Church's divinely appointed authority to teach the truths of religion". In other words, Our Lord gave His Church the authority to teach the faithful about what is expected of them, and that is what the Church has done consistently from the start.

The Magisterium of Catholic Church teaches the faithful in two ways;

1) Solemn Magisterium: is Church teaching which is used only rarely by formal and authentic definitions of councils or Popes. This includes dogmatic definitions by councils or Popes teaching "ex cathedra"
2) Ordinary Magisterium: this second form of Church teaching is continually exercised by the Church especially in her universal practices connected with faith and morals, in the unanimous consent of the Fathers and theologians, in the decisions of the Roman Congregations concerning faith and morals, in the common sense of the Faithful, and various historical documents, in which the faith is declared.

(Definitions from A Catholic Dictionary, 1951) See below for Scripture and Church teaching on the Magisterium of the Church.
 

References In Scripture to the Magisterium of the Church:

• "And the apostles and ancients assembled to consider of this matter. And when there had been much disputing, Peter, rising up, said to them: Men, brethren, you know, that in former days God made choice among us, that by my mouth the Gentiles should hear the word of the gospel, and believe. And God, who knoweth the hearts, gave testimony, giving unto them the Holy Ghost, as well as to us" Acts 15:6-8.
• And later in the same chapter: "For it hath seemed good to the Holy Ghost and to us..." Acts 15:28
• "Go ye into the whole world, and preach the gospel to every creature. He that believeth and is baptized, shall be saved: but he that believeth not shall be condemned." Matthew 16:15

Catholic Church Teaching on the Solemn and Ordinary Magisterium of the Church:

• "All those things are to be believed by divine and Catholic faith which are contained in the written Word of God or in Tradition, and which are proposed by the Church, either in solemn judgment or in its ordinary and universal teaching office, as divinely revealed truths which must be believed." (First Vatican Council, 1870)
• "For this reason the Fathers of the Vatican Council laid down nothing new, but followed divine revelation and the acknowledged and invariable teaching of the Church as to the very nature of faith, when they decreed as follows: "All those things are to be believed by divine and Catholic faith which are contained in the written or unwritten word of God, and which are pro posed by the Church as divinely revealed, either by a solemn definition or in the exercise of its ordinary and universal Magisterium" (Sess. iii., cap. 3)" Encyclical On the Unity of the Church by Pope Leo XIII, 1896
• "But for Catholics nothing will remove the authority of the second Council of Nicea, where it condemns those "who dare, after the impious fashion of heretics, to deride the ecclesiastical traditions, to invent novelties of some kind...or endeavor by malice or craft to overthrow any one of the legitimate traditions of the Catholic Church"; nor that of the declaration of the fourth Council of Constantinople: "We therefore profess to preserve and guard the rules bequeathed to the Holy Catholic and Apostolic Church, by the Holy and most illustrious Apostles, by the orthodox Councils, both general and local, and by everyone of those divine interpreters, the Fathers and Doctors of the Church." Wherefore the Roman Pontiffs, Pius IV and Pius IX, ordered the insertion in the profession of faith of the following declaration: "I most firmly admit and embrace the apostolic and ecclesiastical traditions and other observances and constitutions of the Church." Encyclical On the Doctrine of the Modernists by Pope Pius X, 1907
• "But as the Church was to last to the end of time, something more was required besides the bestowal of the Sacred Scriptures. It was obviously necessary that the Divine Founder should take every precaution, lest the treasure of heavenly-given truths, possessed by the Church, should ever be destroyed, which would assuredly have happened, had He left those doctrines to each one's private judgment. It stands to reason, therefore, that a living, perpetual "magisterium" was necessary in the Church from the beginning, which, by the command of Christ himself, should besides teaching other wholesome doctrines, give an authoritative explanation of Holy Writ, and which being directed and safeguarded by Christ himself, could by no means commit itself to erroneous teaching" Encyclical On the Church in Scotland by Pope Leo XIII, 1898
• "For these writings attack and pervert the true power of jurisdiction of the Roman Pontiff and the bishops, who are the successors of blessed Peter and the apostles; they transfer it instead to the people, or, as they say, to the community. They obstinately reject and oppose the infallible magisterium both of the Roman Pontiff and of the whole Church in teaching matters" Encyclical by Pope Pius IX in 1873, On the Church of Italy, Germany, and Switzerland, under heading of 'Further Heresies'
• "while for subsequent ages down to our own day it continues to be theoretically true that the Church may, by the exercise of this ordinary teaching authority arrive at a final and infallible decision regarding doctrinal questions..." 1917 Catholic Encyclopedia, Infallibility
• "Even the ordinarium magisterium is not independent of the pope. In other words, it is only bishops who are in corporate union with the pope, the Divinely constituted head and centre of Christ's mystical body, the one true Church, who have any claim to share in the charisma by which the infallibility of their morally unanimous teaching is divinely guaranteed according to the terms of Christ's promises" 1917 Catholic Encyclopedia, Infallibility
• "Thus, from the universal agreement of the Church's ordinary teaching authority we have a certain and firm proof, demonstrating that the Blessed Virgin Mary's bodily Assumption into heaven- which surely no faculty of the human mind could know by its own natural powers, as far as the heavenly glorification of the virginal body of the loving Mother of God is concerned-is a truth that has been revealed by God and consequently something that must be firmly and faithfully believed by all children of the Church. For, as the Vatican Council asserts, "all those things are to be believed by divine and Catholic faith which are contained in the written Word of God or in Tradition, and which are proposed by the Church, either in solemn judgment or in its ordinary and universal teaching office, as divinely revealed truths which must be believed." Encyclical On Defining the Dogma of the Assumption by Pope Pius XII, November 1, 1950
• "It need only be added here that not everything in a conciliar or papal pronouncement, in which some doctrine is defined, is to be treated as definitive and infallible. For example, in the lengthy Bull of Pius IX defining the Immaculate Conception the strictly definitive and infallible portion is comprised in a sentence or two; and the same is true in many cases in regard to conciliar decisions." 1917 Catholic Encyclopedia, Infallibility

Examples of the Solemn Magisterium of the Church (also called "ex cathedra teaching"):

• The decisions made during the General Councils of the Catholic Church.
• Papal encyclicals on "The Immaculate Conception" (1849) and "Defining the Dogma of the Assumption" (1950)

Examples of the Ordinary Magisterium of the Church:

• Universal teaching of the Church such as other papal encyclicals (when not written in "ex cathedra" form), universal references such as the Summa Theologica, and writings of Saints that are continually utilized by the Church and passed from Pope to Pope without objection.

Summary

Whatever has been taught by the Catholic Church since the time of Christ, either through "solemn" pronouncements of Councils or Popes, or by unanimous "ordinary" every day teaching, MUST be believed by all Catholics, per what Our Lord said in Scripture and what the first Vatican Council confirmed. Refusing to do so is called "heresy" and places one outside of the Catholic Church.