39 The furtherance of this worthy and meritorious work must be the special endeavor of those who live in the East and who, by mutual esteem, by friendly intercourse, and by the example of their spotless life, can more easily induce our separated brethren, and especially their clergy, to become reunited with the Church. But all the faithful, besides, can contribute by their prayers and supplications that God may establish throughout the world the one Kingdom of the divine Redeemer and His one fold for all.
Source: Orientalis Ecclesiae (Vatican.va)