Infallibility: "This infallibility resides (A) in the pope
personally and alone; (B) in an ecumenical Council subject to papal
confirmation (these infallibilities are distinct but correlative);
(C) in the bishops of the Church, dispersed throughout the world,
teaching definitively in union with the pope. This is not a
different infallibility from (B) but is the ordinary exercise of a
prerogative (hence called the "ordinary magisterium") which is
manifested in a striking manner in an ecumenical Council. This
ordinary magisterium is exercised by pastoral letters, preaching,
catechisms, the censorship of publications dealing with faith and
morals, the reprobation of doctrines and books: it is thus in
continuous function and embraces the whole deposit of faith." “A
Catholic Dictionary”, Attwater, imprimatur 1951
Magisterium: "The official activity of teaching may be exercised
either in the ordinary, or daily, magisterium, or by occasional
solemn decisions. The former goes on uninterruptedly; the latter are
called forth in times of great danger, especially of growing
heresies." Catholic Encyclopedia, 1913
Magisterium: “The Church's divinely appointed authority to teach
the truths of religion…This teaching is infallible. The solemn
magisterium is that which is exercised only rarely by formal and
authentic definitions of councils or Popes... The ordinary
magisterium 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common sense of the Faithful, and various historical documents, in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. All these are founts of a teaching
which as a whole is infallible...” “A Catholic Dictionary”,
Attwater, imprimatur 1951
"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
100 A.D. Scripture is officially complete at the death of the
last Apostle (John). Scripture confirms the Church founded by Christ
cannot teach error, and that those who reject it are condemned. The
Pope and bishops of the Church continue to propagate the infallible
Deposit of Faith (Scripture and tradition) from generation to
generation. This teaching is referred to as the ordinary magisterium
and is infallible. The primary methods of teaching used by the
ordinary magisterium are by preaching and writing
300 A.D. The first 3 centuries of Catholics have lived without any
teaching from the solemn magisterium. They have learned their faith
solely through the ordinary everyday teaching of the popes and
bishops (the infallible ordinary magisterium). The Deposit of Faith
remains completely intact and is infallible
319 A.D. Arius, a Catholic Bishop, is noticed to be preaching a
doctrine on the divinity of Christ that differs from the continuous
teaching of the Church handed down (the ordinary magisterium). The
clergy know the Deposit of Faith handed down so far is infallible,
so when they notice a departure from it, they immediately know it's
heretical. Arius is then corrected by his peers
326 A.D. The Council of Nicaea, the first use of the solemn
magisterium since the founding of the Catholic Church, is called to
order, which condemns Arius and his false doctrine, since he refuses
to recant. The doctrine on the divinity of Christ is already
considered infallible through the day to day teaching of the
ordinary magisterium, and now the Church has confirmed it is
infallible again through the solemn magisterium, so there is
no confusion about it among the faithful
The following centuries A.D. - After the Council of Nicaea, the
ordinary magisterium continues its daily, infallible teaching of the
Deposit of Faith through the popes and bishops of the Church,
keeping it completely intact and unchanged. The solemn magisterium
is used only rarely going forward, which is typically used to
confirm an already-infallible doctrine from the ordinary magisterium
(usually because it has come under attack by heretics)
The Church Fathers and Doctors of the Church assist the popes and
bishops throughout the centuries in clarifying the doctrines that
have been passed down. Should these Fathers and Doctors stray from
the Deposit of Faith, they are corrected by their peers and the
Church resumes as normal. The solemn magisterium is only typically
used when someone refuses to recant on teaching a false doctrine
Encyclicals, catechisms, and other approved Church resources are
published throughout the centuries confirming the individual
doctrines that have been handed down intact and unchanged. These
resources (i.e. catechisms) are not infallible in and of
themselves, but they teach individual, already-infallible
doctrines that have been handed down by the ordinary magisterium
1487 A.D. Scripture confirms that the Catholic Church has always
practiced the prohibition and censorship of books since the
beginning, but with the invention of the printing press, dangerous
books begin to appear far more rapidly. This paves the way for the
Bull of Innocent VIII, which universally prescribes the censorship
of books, and entrusts the bishops with its execution
The imprimatur, an approval by a bishop to permit a book on faith
and morals to be printed, is an affirmation that "the book may,
under present circumstances, be read without detriment to faith or
morals." (Commentary on Canon Law (Augustine 1918), Canon Law
1385). The imprimatur is one of the vehicles used by the ordinary
magisterium to protect the Church from error. In the rare event that
an imprimatur should be mistakenly given to a book that has strayed
from the Deposit of Faith, it is guaranteed that the network of
bishops will catch this. In such a case, if the book is circulated
only a small area, the local bishop may forbid it for his diocese.
However if circulation is widespread, then the Pope may need to
publicly forbid the reading of the book. A future edition of the
book with the error corrected may possibly be published, however it
will require a new imprimatur. Books translated into other languages
also require a new imprimatur
So it can be clearly seen that those Catholics today who use the
excuse to ignore something from the Church, stating that the source
is "not infallible", are mistaken. If a doctrine has been taught
continuously by the ordinary magisterium, it is infallible,
regardless of how the doctrine was relayed to the faithful (i.e. by
catechism, preaching, encyclical etc.)