"By virtue of the mandate entrusted to us by Christ"
Today is the 45th anniversary of the encyclical Humanae Vitae. (Thanks to Rorate Caeli for the reminder.) It is always worth re-reading the encyclical, and when I did so today, one passage struck me as particularly worth recalling, since students of theology may have been told in some faculties that the Church does not have the authority to teach on matters concerning the natural law. Pope Paul VI said:
No member of the faithful could possibly deny that the Church is competent in her magisterium to interpret the natural moral law. It is in fact indisputable, as Our predecessors have many times declared, that Jesus Christ, when He communicated His divine power to Peter and the other Apostles and sent them to teach all nations His commandments, constituted them as the authentic guardians and interpreters of the whole moral law, not only, that is, of the law of the Gospel but also of the natural law. For the natural law, too, declares the will of God, and its faithful observance is necessary for men's eternal salvation. (n.4)Pope Paul expressed his gratitude to the experts and Bishops who had given their opinion and advice, particularly in the Commission set up by Blessed John XXIII to examine the matter. He then said:
However, the conclusions arrived at by the commission could not be considered by Us as definitive and absolutely certain, dispensing Us from the duty of examining personally this serious question. This was all the more necessary because, within the commission itself, there was not complete agreement concerning the moral norms to be proposed, and especially because certain approaches and criteria for a solution to this question had emerged which were at variance with the moral doctrine on marriage constantly taught by the magisterium of the Church.Pope Paul is often thought of as a weak Pope and we are free to discuss that in relation to various aspects of his pontificate. However the encyclical Humanae Vitae was undoubtedly a courageous act - I would say heroic - in which he was fully and explicitly conscious of the duties of his office as the successor of St Peter and of "the mandate entrusted to us by Christ."
Consequently, now that We have sifted carefully the evidence sent to Us and intently studied the whole matter, as well as prayed constantly to God, We, by virtue of the mandate entrusted to Us by Christ, intend to give Our reply to this series of grave questions. (n.6)