infallibility

185. When is the infallibility of the Magisterium Exercised?
890-891
Infallibility is Exercised When the Roman Pontiff, in virtue of his office as the Supreme Pastor of the Church, or the College of Bishops, in junction with the Pope Especially When joined together in an Ecumenical Council, proclaim by a definitive act a doctrine pertaining to faith or morals. Infallibility is Also Exercised When the Pope and Bishops in Their ordinary Magisterium are in agreement in proposing a doctrine as definitive. Every one of the faithful must Adhere to Such Teaching with the obedience of faith.