48 Hence, perfect chastity demands, first, a free choice by Christians before they consecrate themselves to God and then, from God, supernatural help and grace. Our Divine Redeemer Himself has taught us this in the following words: "All men take not his word, but they to whom it is given. . . He that can take it, let him take it." St. Jerome, intently pondering this sacred phrase of Jesus Christ, exhorts all "that each one study his own powers, whether he can fulfill the precepts of virginal modesty. For of itself chastity is charming and attractive to all. But one's forces must be considered, that he who can may take it. The Lord's word is as it were an exhortation, stirring on His soldiers to the prize of purity. He that can take it, let him take it: let him who can, fight, conquer and receive his reward."
Source: Sacra Virginitas (Vatican.va)