always continued in the Church. And just as this one Church cannot err in
faith or morals, since it is guided by the Holy Ghost; so, on the contrary, all
other societies arrogating to themselves the name of church, must
necessarily
be sunk in the most pernicious errors, both doctrinal and
moral.
Catechism of the Catholic Church (1992)
No. 889:
In order to preserve the Church in the purity of the faith
handed on by the apostles, Christ who is the Truth willed to confer on her a
share in his own infallibility. By a supernatural sense of faith the People
of God, under the guidance of the Churchs living Magisterium,
unfailingly adheres to this faith.
No. 890:
The mission of the Magisterium is linked to the definitive
nature of the covenant established by God with his people in Christ. It is
this Magisteriums task to preserve Gods people from deviations and
defections and to guarantee them the objective possibility of professing the
true faith without error. Thus, the pastoral duty of the Magisterium is aimed
at seeing to it that the People of God abides in the truth that liberates. To
fulfil this service, Christ endowed the Churchs shepherds with the charism
of infallibility in matters of faith and morals. The exercise of this charism
takes several forms
No. 892:
Divine assistance is also given to the successors of the
apostles, teaching in communion with the successor of Peter, and, in a
particular way, to the bishop of Rome, pastor of the whole Church, when,
without arriving at an infallible definition and without pronouncing in a
definitive manner, they propose in the exercise of the ordinary
Magisterium a teaching that leads to better understanding of Revelation in
matters of faith and morals. To this ordinary teaching the faithful are to
adhere to it with religious assent which, though distinct from the assent of
faith, is nonetheless an extension of it.