For the past three months I have been immersed in The Apostolic Origins of Priestly Celibacy by the scholarly Jesuit Fr. Christian Cochini (Ignatius Press: San Francisco, 1981). The Apostolic Origins of Priestly Celibacy is the definitive work on the question of priestly celibacy in the Early Church, summarizing all the research done on this question since the Renaissance and adding truly monumental original contributions to this field by his own commentaries on Greek and Latin texts and voluminous compilation of primary sources. Fr. Cochini's magnum opus represents the last word on the question of clerical continence - and the historical sources absolutely vindicate the Tradition of the Church.
The Apostolic Origins of Priestly Celibacy aims to settle four points: (1) That there is a difference historically between the discipline of clerical celibacy and the discipline of clerical continence. (2) That the universal expectation in the Early Church was that clerics, married or unmarried, would observe perfect and perpetual continence. (3) That this was not just a pious custom but an actual law or precept, and (4) That the origins of this law go back to precedents set by the Apostles themselves. Every available text by a father, saint, pope, council, and even imperial legislation is brought to bear to prove these four points. And Fr. Cochini proves them beyond any modicum of doubt.
Honestly, until I read this book, I had not given much thought to the distinction between clerical celibacy and clerical continence. The former means the prohibition of clerics entering into marriage or of married men receiving Holy orders; the latter means abstention from sexual relations by all clerics, married or single. It is undeniable that the Early Church had married priests; some Traditionalists want to deny this plain fact of history. Don't bother. We had married priests. Get over it. In fact, Cochini devotes an entire chapter to documenting every single mention of a married bishop, priest or deacon in the Church of the first seven centuries. That we had married clerics is an undeniable fact of history and anyone who says otherwise has simply not read the sources.
However, the argument does not end there, because - and this is where the modern proponents of a married priesthood totally miss the point - while the Early Church admitted clerics to be married, it never, ever condoned clerics engaging in sexual activity. We are introduced to a plethora of texts - most of them previously unknown to me - in support of this position. For example, the Cum in Utum decretal of Pope Siricius, dating from 386:
"Moreover, as it is worthy, chaste, and honest to do so, this is what we advise: let the priests and Levites have no intercourse with their wives, inasmuch as they are absorbed in the daily duties of their ministries. Paul, when writing to the Corinthians, said, "Leave yourselves free for prayer" (1 Cor. 7:5). If lay people are asked to be continent so that their prayers are granted, all the more so a priest who should be ready at any moment, thanks to an immaculate purity, and not fearing the obligation of offering the sacrifice or baptizing. Were he soiled by carnal concupiscence, what could he do? Would he excuse himself? With what shame, in what state of mind would he carry out his functions?"
There is much more. Hundreds of citations over hundreds of pages drive the main point home: It has never been the tradition of the Church to condone a sexually active priesthood.
There are many things cleared up by understanding this discipline. For one thing, it handily explains the how the Church once allowed then prohibited married clerics while simultaneously claiming her teaching on this matter has never changed; this is because the teaching was never about whether a cleric could be married, but whether it was fitting for clerics to have sexual intercourse. Understood this way, the teaching (until modern times) has been unanimous.
It also puts the question of marriage in the Eastern Rites into a glaringly new perspective. When we understand the ancient discipline, we see that it is not, as so often asserted, that the Western Church imposed a new discipline onto its clerics while the East, which allows married priests, is preserving a more ancient practice. On the contrary, East and West both insisted on continence from their clerics. In the West, this insistence remained so strong that eventually it became clear that the only way to ensure it was to prohibit the ordination of married men (the discipline of celibacy); in the East, the observance of the ancient canons began to grow lax until after the Quinisext Council of 692, married clerics were finally allowed to use the marital rights. Thus it was the East that changed the discipline, not the West.
I highly recommend Fr. Cochini's book for anyone who wants a solid patristic understanding of this question. You can purchase it here on Amazon.
If you want an in depth but more concise synopsis of the historical arguments presented in Cochini's book, please see my article "The Truth About Priestly Celibacy and Continence in the Early Church" on the USC website, which synthesizes the most important primary sources cited by Cochini and explains their theological and historical significance.