77 The Council of Trent pronounced this to be a parish priest's first and greatest duty and everyone knows what immense and constant labor John Vianney expended in order to be equal to carrying out this task. For he began his course of studies when he was already along in years, and he had great difficulty with it; and his first sermons to the people kept him up for whole nights on end. How much the ministers of the word of God can find here to imitate! For there are some who give up all effort at further study and then point too readily to his small fund of learning as an adequate excuse for themselves. They would be much better off if they would imitate the great perseverance of soul with which the Cure of Ars prepared himself to carry out this great ministry to the best of his abilities: which, as a matter of fact, were not quite as limited as is sometimes believed, for he had a clear mind and sound judgment. (81)
Source: Sacerdotii Nostri Primordia (Vatican.va)