Chastity (Lat. castitas), in the Christian sense, denotes (1.) freedom from impure thoughts, desires, or imaginations; and (2.) abstinence from illicit sexual intercourse. It requires a control of the passions and of the imagination to a degree which no system of morals, except the Christian, has ever succeeded in securing. The love of God in the heart is the only sure safeguard against evil lusts. The body, in Christian ethics, is "the temple of the Holy Ghost." But, apart from pure religious life, a strict morality may do a great deal toward securing purity, if not of heart, at least of life. The evil consequences of sexual disorder should be taught in morals as hindrances to lust. Among them is the certainty that domestic happiness, as well as the physical and mental health of the criminal, are endangered by it. Chastity is the noblest result of pure morality, or of the free mastery of spiritual elevation and purity over the natural instincts; it protects liberty from sinking into subjection to the flesh, so far only, however, as his the result of virtue, not of a natural indifference arising from temperament.
The best sources of chastity are, first, the true fear of God, which leads to avoid offending God by a sinful misuse of the noblest force of nature, and disturbing the divine law of human reproduction by beastly indulgences; secondly, education, inculcating honesty, modesty, and morality; thirdly, active occupation both of mind and body; fourth, moderation in the use of drink and spices. Chastity is highly blessed in its results, for from it result the purity of the soul, the liberty of the will, the preservation of health and strength, and freedom from the difficulties and misfortunes which unchastity entails on its unfortunate victims. It is also the seal of a high mind, a true virtue, and a sincere fear of God (Mr 7:21-22; Ro 13:13, Let us walk honestly, as in the day: not in rioting and drunkenness, not in chambering and wantonness, not in strife and envying; 2Co 6:4,6; Ga 5:19-22; 1Co 7:5, Defraud ye not one the other, except it be with consent for a time, that ye may give yourselves to fasting and prayer; and come together again, that Satan tempt you not for your incontinency; Php 4:8; 1Ti 4:12; 1Ti 5:2; Tit 1:8; Tit 2:5; 1Pe 1:22; 1Pe 3:2, While they behold your chaste conversation coupled with fear; 4:3, For the time past of our life may suffice us to have wrought the will of the Gentiles, when we walked in lasciviousness, lusts, excess of wine, revellings, banquetings, and abominable idolatries; Jas 3:17). He who is under the guidance of divine wisdom is essentially chaste (Jas 4:8). Those who are δίψυχοι, double-minded, cling on the one side to the earth, and on the other aspire after heaven. When the heart is purified by the spirit of God, this duality ceases, and chastity is easy. — Krehl, N.T. Handwörterbuch, s.v.