2 From the apostolic letter Praeclara published last June, you know that We invited and urged all nations to the unity of the Christian faith. Thus, through Us the divine promise of "one sheepfold and one Pastor" would be realized. You have learned from Our recent apostolic letters concerning the safeguarding of the Eastern Rites that We look with special care to the East and its churches, renowned and venerated by many names. From these same letters you have learned the procedures by which, in consultation with the Eastern patriarchs, We have investigated how to bring about more readily the desired end, namely the union of the Roman and Eastern Catholic Churches. We do not deny that this goal involves great difficulties. To overcome them, Our strength is not sufficient; nevertheless We confidently judge that the necessary strength of trust and of constancy is found in God. For He who motivated Us to undertake this mission will in His providence certainly supply the strength and the resources to complete it. And this is what We implore from Him, and We exhort all the faithful to also pray earnestly for this. Since the divine help must necessarily be joined with human effort, it is right for Us therefore to expend special care in seeking and supporting whatever seems to contribute to the end We have in view.
Source: Christi Nomen (Vatican.va)