16 In what has been said we have faithfully described the exemplar and form of the Church as divinely constituted. We have treated at length of its unity: we have explained sufficiently its nature, and pointed out the way in which the Divine Founder of the Church willed that it should be preserved. There is no reason to doubt that all those, who by Divine Grace and mercy have had the happiness to have been born, as it were, in the bosom of the Catholic Church, and to have lived in it, will listen to Our Apostolic Voice: "My sheep hear my voice" (John x., 27), and that they will derive from Our words fuller instruction and a more perfect disposition to keep united with their respective pastors, and through them with the Supreme Pastor, so that they may remain more securely within the one fold, and may derive therefrom a greater abundance of salutary fruit. But We, who, notwithstanding our unfitness for this great dignity and office, govern by virtue of the authority conferred on us by Jesus Christ, as we "look on Jesus, the author and finisher of our faith" ( Heb . xii., 2) feel Our heart fired by His charity. What Christ has said of Himself We may truly repeat of Ourselves: "Other sheep I have that are not of this fold: them also I must bring and they shall hear my voice" ( John x., 16). Let all those, therefore, who detest the wide-spread irreligion of our times, and acknowledge and confess Jesus Christ to be the Son of God and the Saviour of the human race, but who have wandered away from the Spouse, listen to Our voice. Let them not refuse to obey Our paternal charity. Those who acknowledge Christ must acknowledge Him wholly and entirely. "The Head and the body are Christ wholly and entirely. The Head is the only-begotten son of God, the body is His Church; the bridegroom and the bride, two in one flesh. All who dissent from the Scriptures concerning Christ, although they may be found in all places in which the Church is found, are not in the Church; and again all those who agree with the Scriptures concerning the Head, and do not communicate in the unity of the Church, are not in the Church" (S. Augustinus, Contra Donatistas Epistola , sive De Unit. Eccl. , cap. iv., n. 7). And with the same yearning Our soul goes out to those whom the foul breath of irreligion has not entirely corrupted, and who at least seek to have the true God, the Creator of Heaven and earth, as their Father. Let such as these take counsel with themselves, and realize that they can in no wise be counted among the children of God, unless they take Christ Jesus as their Brother, and at the same time the Church as their mother. We lovingly address to all the words of St. Augustine: "Let us love the Lord our God; let us love His Church; the Lord as our Father, the Church as our Mother. Let no one say, I go indeed to idols, I consult fortune-tellers and soothsayers; but I leave not the Church of God: I am a Catholic. Clinging to thy Mother, thou offendest thy Father. Another, too, says: 'Far be it from me; I do not consult fortune - telling, I seek not soothsaying, I seek not profane divinations, I go not to the worship of devils, I serve not stones: but I am on the side of Donatus.' What doth it profit thee not to offend the Father, who avenges an offence against the Mother? What doth it profit to confess the Lord, to honour God, to preach Him, to acknowledge His Son, and to confess that He sits on the right hand of the Father, if you blaspheme His Church? . . . If you had a beneficent friend, whom you honoured daily - and even once calumniated his spouse, would you ever enter his house? Hold fast, therefore, O dearly beloved, hold fast altogether God as your Father, and the Church as your Mother" (Enarratio in Psal. lxxxviii., sermo ii., n. 14). Above all things, trusting in the mercy of God, who is able to move the hearts of men and to incline them as and when He pleases, We most earnestly commend to His loving kindness all those of whom We have spoken. As a pledge of Divine grace, and as a token of Our affection, We lovingly impart to you, in the Lord, Venerable Brethren, to your clergy and people, Our Apostolic Blessing.
Source: Satis Cognitum (Vatican.va)