25 And since silence or indolence on our part, as unfortunately is not unfrequently the case among the good, would incriminate us too, let every one of the sacred Pastors take as said to himself for the defense of his flock, and bring home to others in due season, Anselm's words to the mighty Prince of Flanders: "As you are my Lord and truly beloved by me in God, I pray, conjure, admonish and counsel you, as the guardian of your soul, not to believe that your lofty dignity is diminished if you love and defend the liberty of the Spouse of God and your Mother, the Church, not to think that you abase yourself when you exalt her, not to believe that you weaken yourself when you strengthen her. Look round you and see; the examples are before you; consider the princes that attack and maltreat her, what do they gain by it, what do they attain? It is so clear that there is no need to say it" ( Epist., lib . iv. ep. 32). And all this he explains with his usual force and gentleness to the powerful Baldwin, King of Jerusalem: "As your faithful friend, I pray, admonish, and conjure you, and I pray God that you live under God's law and in all things submit your will to the will of God. For it is only when you reign according to the will of God that you reign for your own welfare. Nor permit yourself to believe, like so many bad kings, that the Church of God has been given to you that you may use her as a servant, but remember that she has been recommended to you as an advocate and defender." In this world God loves nothing more than the liberty of His Church . "They who seek not so much to serve as to rule her, are clearly acting in opposition to God. God wills His Spouse to be free and not a slave. Those who treat her and honor her as sons surely show that they are her sons and the sons of God, while those who lord it over her, as over a subject, make themselves not children but strangers to her, and are therefore excluded from the heritage and the dower promised to her" ( Ibid . ep. 8). Thus did he unbosom his heart so full of love for the Church; thus did he show his zeal in defense of her liberty, so necessary in the government of the Christian family and so dear to God, as the same great Doctor concisely affirmed in the energetic words: "In this world God loves nothing more than the liberty of His Church." Nor can We, venerable brethren, make known to you Our feelings better than by repeating that beautiful expression.
Source: Communium Rerum (Vatican.va)