O God! would that we could see this spectacle! What joy would it be for thy church on earth, in the midst of so many rude combats, and such bitter affliction! What joy for the church in heaven! And what joy, churches of the East, for your doctors and your saints, "when from the height of heaven they see union established with the apostolic see, centre of catholic truth and unity; a union that, during their life here below, they labored to promote, to teach by all their studies, and by their indefatigable labors, by their doctrine and their example, inflamed as they were with the charity poured into their hearts by the Holy Spirit, for Him who has reconciled and purchased peace at the price of his blood; who wished that peace should be the mark of his disciples, and who made this prayer to his Father, 'May they be one as we are one.'" [Footnote 15] [Footnote 15: _Ibidem_. Unity will be the eternal characteristic of the true church. Every question concerning the church is reduced finally to this question, _Where is unity?_] {25} Oh! then, listen to the language of the church, the true church of Jesus Christ, who alone, among all Christian societies, raises a maternal voice, and demands again all her children, because she is their true mother! This is the reason why the Sovereign Pontiff, after he has spoken to the separated East, turns toward other Christian yet not catholic communions, and addresses to all our brothers of Protestantism the same urgent appeal. Protestantism! "Ah!" exclaimed Bossuet, in his ardent love, in his zealous wish for unity, "our heart beats at this name, and the church, always a mother, can never, when she remembers it, repress her sighs and her desires." These are sighs and desires which we have heard from the Holy Father in an apostolic letter written a few days after the Brief addressed to the Eastern bishops, to "all Protestants and other non-Catholics," and in which he deplores the misfortunes of separation, and shows the great advantage of the unity desired by our Lord. "He exhorts, he begs all Christians separated from him to return to the cradle of Jesus Christ. ... In all our prayers and supplications we do not cease to humbly ask for them, both day and night, light from heaven, and abundant grace from the eternal Pastor of souls, and with open arms we are waiting for the return of our wandering children." [Footnote 16] [Footnote 16: Apostolic Letters of September 13th, 1868.]