66 This will be proved by the firmness of the spirit with which he accepts the personal and community type of discipline demanded by the priestly life. Such a regime, the lack or deficiency of which is to be deplored because it exposes the candidate to grave disorders, should not be borne only as an imposition from without. It should be inculcated and implanted as an indispensable component within the context of the spiritual life.
Source: Sacerdotalis Caelibatus (Vatican.va)