In Matthew 19:12 Christ suggests His male disciples may want to make themselves (figurative) eunuchs for the sake of the kingdom of heaven. In Orthodox Jewish culture, men are expected to obey God’s directive to reproduce and sire offspring; Jewish women still judge barrenness a stigma. Why would Christ incur the wrath of Jewish traditionalists by contradicting this? What was so important about chaste celibacy that Jesus would encourage the practice, even for His married Apostles?

Jesus himself used a canine metaphor with the Canaanite woman in Matthew 15:26, so we can make an analogy with “man’s best friend.” Humans over time found the benefits of “fixing” their dogs, who then are not driven to wanderlust for a mate, sustain fewer injuries from competitive behavior, carry less disease and infection, and are more loving and devoted to their masters. This sheds light when applied to human behavior. St. Paul, being himself single, exhorted Christians to celibacy, as he knew such devotees are more likely to direct their full attention to serving and pleasing God instead of a spouse and offspring (cf. 1 Cor. 7:33).

Such self-control is crucial in living a religious vocation. Celibate men and women are content in simplicity, and the frugal diets and abstemious habits of the monastery or convent promote health and long life. Not anxious to pursue family, fame, and fortune, devout monastics avoid stressful multiplication of sorrows and certain “travails of the flesh.” As Jesus promised His disciples, My yoke is easy, my burden, light (Matt 11:30).

Pharaohs and emperors promoted eunuchs who were unmoved by desire for sex, wealth, and power, appointing them as treasurers, generals, and guardians. God’s holy virgins are likewise entrusted with the keys of the kingdom (Matt 16:19) and are gifted with miracle healings, prophecies, and uncanny insights as spiritual confessors.

When his hearers were tempted to worship him like a proxy god, St. Paul had to proclaim he was merely an obedient and faithful messenger (Acts 14:12-15). By being “God’s best friend,” he could hear his Master’s voice and defend Christ’s teachings unto martyrdom.

In the Latin Church, the tradition of clerical continence developed into the ordination of only unmarried men from the 11th century onward. The discipline became a formal part of canon law in 1917.