11 The wonderful devotion in this regard of St. John Vianney—a man who was "hard on himself, and gentle with others" (11) —was so outstanding that it should serve as a clear and timely reminder of the important role that priests should attribute to the virtue of penance in striving for perfection in their own lives. Our predecessor of happy memory, Pius XII, in order to give a clear picture of this doctrine and to clear up the doubts and errors that bothered some people, denied that "the clerical state—as such, and on the basis of divine law—requires, of its very nature or at least as a result of some demand arising from its nature, that those enrolled in it observe the evangelical counsels," (12) and justly concluded with these words: "Hence a cleric is not bound by virtue of divine law to the evangelical counsels of poverty, chastity, obedience." (13)
Source: Sacerdotii Nostri Primordia (Vatican.va)