Jesus' saying about eunuchs can sound startling because the social category is unfamiliar to many modern readers. Eunuchs were recognizable figures in the ancient Mediterranean and Near Eastern world, often associated with royal courts and administrative service.
Jesus distinguishes different reasons a person might be a eunuch and then uses the category to speak about voluntary celibacy for the kingdom.
Some males were eunuchs because of physical conditions from birth, while others were castrated, sometimes in connection with service in royal households. Ancient court systems could employ eunuchs in positions of trust and access.
Jesus' third category, those who have "made themselves eunuchs for the kingdom of heaven," is best understood from the saying's context as deliberate renunciation of marriage rather than a command to self-mutilation. Early Christian interpretation generally recognized the figurative force of the expression despite occasional notorious misreadings.
The historical category makes Jesus' metaphor intelligible. He takes a known social condition and uses it to describe a demanding vocation in which some people remain unmarried for the sake of God's kingdom.
The saying also follows a difficult discussion of marriage and divorce, showing that Jesus does not present marriage as the only faithful path. Celibacy, however, is described as a gift or calling that not everyone can receive.