Catechism of the Catholic Church

2346 Charity is the form of all the virtues. Under its influence, chastity appears as a school of the gift of the person. Self-mastery is ordered to the gift of self. Chastity leads him who practices it to become a witness to his neighbor of God's fidelity and loving kindness.

2347 The virtue of chastity blossoms in friendship. It shows the disciple how to follow and imitate him who has chosen us as his friends, ¹³⁴ who has given himself totally to us and allows us to participate in his divine estate. Chastity is a promise of immortality.

Chastity is expressed notably in friendship with one's neighbor. Whether it develops between persons of the same or opposite sex, friendship represents a great good for all. It leads to spiritual communion.