19 A Bishop, or a priest of the true Church of Christ, ought time and again to meditate on what the Apostle Paul said of his preaching of the Gospel: "For I give you to understand, brethren, that the gospel which was preached by me is not of man. For I did not receive it from man, nor was I taught it; but I received it by a revelation of Jesus Christ" ( Gal . 1. 11-12)
Source: Ad Sinarum Gentem (Vatican.va)