Humani Generis Redemptionem §15

¹⁵ Let us now consider what the Apostle's spiritual preparation for preaching was. The three qualities of his equipment most worthy of note are these: First of all he was a man who always fully conformed himself to God's will. No sooner was he smitten, when on the road to Damascus, by the power of the Lord Jesus than he uttered that cry so worthy of an apostle: "Lord what will thou have me to do?" [ Acts ix:6] For then and there as ever afterwards, for Christ's sake he was indifferent to toil or rest, to poverty or wealth, to praise or contempt, to life or death. There can be no doubt that he made such progress in the apostolate because he conformed with such perfect submission to the will of God. Wherefore like St. Paul, every preacher devoted to the salvation of souls should be first of all so zealous for God's service as to feel no concern about who his hearers are to be, what success he will have, or what fruits he is to reap. He should have an eye not to his own advantage but to God's glory.