«SUMMI PONTIFICATUS». — The first encyclical of Pius XII (20 October 1939), in which the program of his pontificate is outlined.
Published on the eve of the feast of Christ the King, in the fortieth year of Annum sacrum, with which Leo XIII consecrated the world to the Sacred Heart, the Pontiff begins by recalling the faithful to this supreme source of spiritual blessings; he then expresses the joy he experienced at the cordial and universal outpouring of congratulations that reached him on his elevation to the throne, including from non-Catholics. The tributes paid by heads of state were a source of particular satisfaction, especially those from Italy, where the Lateran Pacts marked the beginning of peaceful and fruitful relations.
In outlining his program, he proposes above all «to bear witness to the truth with apostolic firmness», presenting with impartiality and paternal charity the errors and faults that must be known in order to remedy them. The Pope locates the root of modern errors in the denial of a universal morality, for which Protestantism is responsible. The gravest consequences are: 1) the loss of the sense of human solidarity in Adam and in Christ; 2) the absolute authority of civil power, which fails to respect the rights of the family and does not consider itself bound by fidelity to freely contracted international agreements. Against the first error, the Supreme Pontiff sets the example of the Church in her missionary activity, open to the values of all civilizations; against the second, he recalls the inviolable rights of the family and the obligation of conscience founded on the very nature of man. This is followed by an exhortation to the collaboration of the laity in the apostolate, which begins in the Christian family, extends to the defense of Christian principles in civil society (especially the Church’s rights regarding the education of youth), and reaches the political sphere through effective peace-making activity. The encyclical concludes with a supreme appeal for common cooperation to alleviate the anguish of war where it has already begun and to avert it in other parts of the world.