22 It is that they may acquire this spiritual liberty of body and soul, and that they may be freed from temporal cares, that the Latin Church demands of her sacred ministers that they voluntarily oblige themselves to observe perfect chastity. And "if a similar law," as Our predecessor of immortal memory Pius XI declared, "does not bind the ministers of the Oriental Church to the same degree, nevertheless among them too ecclesiastical celibacy occupies a place of honor, and, in certain cases, especially when the higher grades of the hierarchy are in question, it is a necessary and obligatory condition."
Source: Sacra Virginitas (Vatican.va)