It is Jesus himself who wanted the Pope to have a Magisterium of authority, having entrusted him with the mission of teaching men the truths to be believed and the duties to be fulfilled. In promulgating “Humanae Vitae” Paul VI acted within and by force of this Magisterium. He proposed anew “a teaching which is based on the natural law as illuminated and enriched by divine Revelation.” Paul VI therefore says: “Let no Catholic be heard to assert that the interpretation of the natural moral law is outside the competence of the church’s Magisterium. It is in fact indisputable, as our Predecessors have many times declared (Pius XI, St. Pius X, Pius XII and John XXIII are cited), that Jesus Christ, when he communicated his divine power to Peter and the other Apostles and sent them to teach all nations his commandments (cf. Mt. 28:18029), 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, the reason being that the natural law declares the will of God, and its faithful observance is necessary for men’s eternal salvation” (“Humanae Vitae”, n. 4)…