Concerning Virgins I Have No Commandment

"About Celibacy, I Have No Instructions from the Lord"

The insistence on clerical celibacy was established in much of the Western Church beginning in the Fourth Century. It expanded slowly and unevenly throughout Late Antiquity and the early middle ages and at the Second Lateran Council in 1139 became Church Law. This Law of Celibacy decreed that Holy Orders were a absolute impediment to any in the higher clerical orders attempting to contract marriage. Any such marriage was automatically null and void in the eyes of the Church.

Nicene and Post-Nicene Fathers

NPNF1-12. Saint Chrysostom: Homilies on the Epistles of Paul to the Corinthians