185. When is the infallibility of the Magisterium exercised?

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 union 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.

Further reading: CCC 890-891

186. How do Bishops exercise their ministry of sanctification?

Bishops sanctify the Church by dispensing the grace of Christ by their ministry of the word and the sacraments, especially the Holy Eucharist, and also by their prayers, their example and their work.

Further reading: CCC 893

187. How do the Bishops exercise their function of governing?

Every bishop, insofar as he is a member of the college of bishops, bears collegially the care for all particular Churches and for the entire Church along with all the other bishops who are united to the Pope. A bishop to whom a particular Church has been entrusted governs that Church with the authority of his own sacred power which is ordinary and immediate and exercised in the name of Christ, the Good Shepherd, in communion with the entire Church and under the guidance of the Successor of Peter.

Further reading: CCC 894-896