8 All this good, which affords the best hopes for the future of France, must not only be preserved, but increased by united efforts and constant watchfulness. Above all, care must be taken that the ranks of the clergy shall be more and more filled with worthy and capable men. Let the authority of their Bishops be sacred to the priest; let the latter be convinced that their ministry will be neither holy, nor profitable, nor respected, if it be not exercised under the guidance of their Bishops. The prominent laymen also, those devoted to Our common Mother the Church, and who are able to render useful service to the Catholic religion by their word and by their pen, must multiply their efforts in the defence of the Church. To obtain these results, it is an absolute necessity that wills should be in harmony, and the action unanimous. There is certainly nothing more wished for by Our adversaries than dissensions between Catholics, who should avoid nothing with greater care than any disagreement, mindful of the Divine words: "Every kingdom divided against itself shall be made desolate."
Source: Nobilissima Gallorum Gens (Vatican.va)