At some point in their discernment process, most priests and religious likely thought, “I think I’d love being a (priest/brother/sister), but I would have a hard time being celibate.”
If there’s one universal roadblock to a priestly or religious vocation, that’s it. Ask a young man or worman who is struggling with discernment, and odds are you’ll hear this concern.
In answer to this concern, reading Pope Saint John Paul II’s Theology of the Body, a collection of addresses from 129 of his general audiences on human sexuality, is the perfect solution. Of course, some may find it daunting to read through the whole collection. Fortunately, there are some great sources to help break it down for discerners, like www.theologyofthebody.net or the book Theology of the Body for Beginners: A Basic Introduction to Pope John Paul II's Sexual Revolution, by Christopher West.
The main principle that is applicable to discerning celibacy can be summed up relatively simply: Celibacy is a gift given to a chosen few which helps each of us to better understand God's call to the Kingdom of Heaven.
A selected passage from St. John Paul himself is a great place to start understanding why God calls some men and women to be celibate:
“One cannot live a celibate vocation without being chosen by God and given the gift of his grace. This is good news! If you are called to a priestly or religious vocation, God will grant you the grace needed for an abundant, joyful, celibate life.
“Those able ‘to receive it’ are those ‘to whom it has been given.’ The words quoted clearly indicate the importance of the personal choice and also the importance of the particular grace, that is, of the gift which man receives to make such a choice. It may be said that the choice of continence for the kingdom of heaven is a charismatic orientation toward that eschatological state in which men "neither marry nor are given in marriage.
“By accepting man’s efforts, God crowns his own work by giving a new grace. Right from the beginning, this aspiration has been his gift. ‘Being anxious how to please God’ is therefore a contribution of man in the continual dialogue of salvation that God has begun. Evidently, every Christian who lives his faith takes part in this dialogue.
However, Paul observes that the man who is bound by the marriage bond "is divided" (1 Cor 7:34) by reason of his family obligations (cf. 1 Cor 7:34). From this remark it apparently follows that the unmarried person would be characterized by an interior integration, by a unification that would allow him to dedicate himself completely to the service of the kingdom of God in all its dimensions. This attitude presupposes abstention from marriage, exclusively for the sake of the kingdom of God, and a life uniquely directed to this goal.”
Pope John Paul II. "Virginity or Celibacy for the Sake of the Kingdom."
General Audience of Wednesday 10 March, 1982. L'Osservatore Romano English Edition. https://www.ewtn.com/catholicism/library/virginity-or-celibacy-for-the-sake-of-the-kingdom-8535
