12 The chastity "for the sake of the kingdom of heaven" (Matt. 19:12) which religious profess should be counted an outstanding gift of grace. It frees the heart of man in a unique fashion (cf. 1 Cor. 7:32-35) so that it may be more inflamed with love for God and for all men. Thus it not only symbolizes in a singular way the heavenly goods but also the most suitable means by which religious dedicate themselves with undivided heart to the service of God and the works of the apostolate. In this way they recall to the minds of all the faithful that wondrous marriage decreed by God and which is to be fully revealed in the future age in which the Church takes Christ as its only spouse. Religious, therefore, who are striving faithfully to observe the chastity they have professed must have faith in the words of the Lord, and trusting in God's help not overestimate their own strength but practice mortification and custody of the senses. Neither should they neglect the natural means which promote health of mind and body. As a result they will not be influenced by those false doctrines which scorn perfect continence as being impossible or harmful to human development and they will repudiate by a certain spiritual instinct everything which endangers chastity. In addition let all, especially superiors, remember that chastity is guarded more securely when true brotherly love flourishes in the common life of the community. Since the observance of perfect continence touches intimately the deepest instincts of human nature, candidates should neither present themselves for nor be admitted to the vow of chastity, unless they have been previously tested sufficiently and have been shown to possess the required psychological and emotional maturity. They should not only be warned about the dangers to chastity which they may meet but they should be so instructed as to be able to undertake the celibacy which binds them to God in a way which will benefit their entire personality.
Source: Perfectae Caritatis (Vatican.va)