60 The wonderful examples of priestly asceticism and prayer that We have proposed for your consideration up to now, Venerable Brethren, also point clearly to the source of the pastoral skill and of the truly remarkable heavenly effectiveness of the sacred ministry of St. John M. Vianney. In this regard, Our predecessor of happy memory, Pius XII, gave a wise warning: "The priest should realize that the important ministry entrusted to him will be more fruitfully carried out, the more intimately he is united with Christ and led on by His spirit." (70) As a matter of fact, the life of the Cure of Ars offers one more outstanding argument in support of the supreme rule for apostolic labor that was laid down by Jesus Christ Himself: "Without me, you can do nothing." (71)
Source: Sacerdotii Nostri Primordia (Vatican.va)