74 Christ's priest will daily receive new strength and joy as he deepens in meditation and prayer the motives for his gift and the conviction that he has chosen the better part. He will ask humbly and perseveringly for the grace of fidelity, never denied to those who ask it sincerely. At the same time he will use the natural and supernatural means at his disposal. In particular he will not disregard those ascetical norms which have been substantiated by the Church's experience and are no less necessary in modern circumstances than in former times. (121)
Source: Sacerdotalis Caelibatus (Vatican.va)