Fernando Gallego, “Cristo Bendiciendo” (c. 1495)
“In the Latin Church the sacrament of Holy Orders for the presbyterate is normally conferred only on candidates who are ready to embrace celibacy freely and who publicly manifest their intention of staying celibate for the love of God's kingdom and the service of men.” (CCC 1599)
With regard to clerical, or priestly celibacy, Protestants (and today, many Catholics) often think that chastity is virtually impossible, and not biblical. Our Lord Jesus and St. Paul were of a different opinion. Jesus said:
Matthew 19:12 (RSV) For there are eunuchs who have been so from birth, and there are eunuchs who have been made eunuchs by men, and there are eunuchs who have made themselves eunuchs for the sake of the kingdom of heaven. He who is able to receive this, let him receive it.
One might argue that Jesus was merely describing this state of affairs, not sanctioning it, but this is made implausible by His concluding comment, “He who is able to receive this, let him receive it.”
St. Paul agreed, as he expressed in great detail:
1 Corinthians 7:7-8, 28, 32-35, 38 I wish that all were as I myself am. But each has his own special gift from God, one of one kind and one of another.  To the unmarried and the widows I say that it is well for them to remain single as I do. . . .  But if you marry, you do not sin . . . Yet those who marry will have worldly troubles, and I would spare you that. . .  I want you to be free from anxieties. The unmarried man is anxious about the affairs of the Lord, how to please the Lord;  But the married man is anxious about worldly affairs, how to please his wife,  and his interests are divided. And the unmarried woman or girl is anxious about the affairs of the Lord, how to be holy in body and spirit; . . .  I say this for your own benefit, not to lay any restraint upon you, but to promote good order and to secure your undivided devotion to the Lord . . .  So that he who marries his betrothed does well; and he who refrains from marriage will do better.
These verses form the scriptural rationale for the much-maligned Catholic requirement of celibacy for priests, monks, and nuns. St. Paul's argument is clear: the celibate priest can singleheartedly devote himself both to God and his flock.
Why, then, is there so much controversy today over this disciplinary requirement (it is neither a dogma nor irreversible, although it is firmly established in Catholic tradition)? I submit that it is a lack of belief in the power of God to assist one in such a difficult life-choice (especially given the present sexually crazed atmosphere).
It needs to be stressed that no one is forced to be celibate. It is both a matter of personal choice, and, on a deeper level, an acceptance of one's calling, as given by God. Paul acknowledges both the divine impetus (1 Corinthians 7:7, 20) and the free will initiative of human beings (7:35, 38). These two are not contradictory, but rather, complementary.
In other words, if a man is called to celibacy (and further, to the priesthood in the Latin, Western Rites), he will be given both the desire and the ability to carry out this lifestyle successfully (see Philippians 2:13). If one is not called, like most of us, to celibacy and/or the priesthood, then he or she ought to get married (1 Corinthians 7:7, 9, 20, 28, 38).
The issue is not a matter of either/or, with one option being good and the other bad. Both are good, but one has a certain practical superiority and an obviously somewhat heroic aspect. To personally renounce something is not equivalent to regarding the state or thing renounced evil. I may give up eating potatoes, reading fiction, ice skating, or swimming, for various and sundry reasons, but this does not make any of them evil in and of themselves.
Likewise, the Catholic Church is not in any sense whatsoever against marriage, or sexuality (7:38), as long as these are within the proper biblical and moral guidelines. Marriage and ordination are both sacraments in Catholicism; both are positive and wonderful means of God's grace. The Church only wants to see everyone fulfill the estate in life to which they are called (7:20).
No one is compelled to become a Catholic priest, and anyone who is not called to celibacy is free to become a married priest in the Eastern Rites of the Catholic Church, where married men can be ordained.
Every institution has the inherent right to create whatever rules and regulations it deems necessary for its purposes. In this case, the Catholic Church is simply trying to follow the clear recommendations of its Lord and one of the premier apostles, St. Paul.
Furthermore, today there seems to be a lack of understanding (or downright denigration) of the validity and seriousness of vows and oaths, from the biblical and Christian perspective. We see how lightly the marital vows are taken by many in our time (“for better or worse” and “till death do us part” are almost forgotten by thousands, it seems).
The Law of Moses made vows and oaths sacredly and solemnly binding (Exodus 20:7, Leviticus 19:12, Deuteronomy 5:11, 23:21-23). Ezekiel says that perjury is punishable by death (Ezekiel 17:16-18). Jesus taught that oaths were binding (Matthew 5:33). Even God bound Himself by an oath (Hebrews 6:13-18). The notion of covenant is closely related to oath-taking. A deceptive vow is an affront to God, and brings about His curse (Malachi 1:14, Ecclesiastes 5:4-5). Vowing is completely voluntary and optional in biblical thought, but once made, the vow must be performed and is a very serious matter indeed.
No one maintains that abstention from sex is easy. But no amount of admitted difficulty or self-serving rationalization can undo the plain teaching of Holy Scripture in this regard. Priests (like all of us) are fallen human beings, subject to temptations and moral lapses, and are special targets of Satan due to their lofty office. They need our prayers continually.