"It is written (Tob. 4:13): 'Take heed
to keep thyself. . . from all fornication, and beside thy wife never endure to know a
crime.' Now crime denotes a mortal sin. Therefore fornication and all intercourse with
other than one's wife is a mortal sin." - St. Thomas Aquinas ("Summa
Theologica" 13th century A.D.)
"Flee fornication. Every sin that a man doeth is without the body; but he that
committeth fornication sinneth against his own body." - 1 Corinthians 6:18
"For from within, out of the heart of men, proceed evil thoughts, adulteries,
fornications, murders, thefts, covetousness, wickedness, deceit, lasciviousness, an evil
eye, blasphemy, pride, foolishness: All these evil things come from within, and defile the
man." - Mark 7:21-23
"Marriage [is] honourable in all, and the bed undefiled: but whoremongers and
adulterers God will judge." - Hebrews 13:4
"Mortify therefore your members which are upon the earth; fornication,
uncleanness, inordinate affection, evil concupiscence, and covetousness, which is
idolatry: For which things' sake the wrath of God cometh on the children of
disobedience...." - Colossians 3:5-6
"But fornication, and all uncleanness, or covetousness, let it not be once named
among you, as becometh saints; Neither filthiness, nor foolish talking, nor jesting, which
are not convenient: but rather giving of thanks. For this ye know, that no whoremonger,
nor unclean person, nor covetous man, who is an idolater, hath any inheritance in the
kingdom of Christ and of God." - Ephesians 5:3-5
"[This] I say then, Walk in the Spirit, and ye shall not fulfil the lust of the
flesh. For the flesh lusteth against the Spirit, and the Spirit against the flesh: and
these are contrary the one to the other: so that ye cannot do the things that ye would.
But if ye be led of the Spirit, ye are not under the law. Now the works of the flesh are
manifest, which are [these]; Adultery, fornication, uncleanness, lasciviousness, idolatry,
witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, envyings,
murders, drunkenness, revellings, and such like: of the which I tell you before, as I have
also told [you] in time past, that they which do such things shall not inherit the kingdom
of God." - Galatians 5:16-21
What Catechism of the Catholic Church says on
"Pre-Marital Sex:"
2353. "Fornication is carnal union between an unmarried man and an
unmarried woman. It is gravely contrary to the dignity of persons and of human sexuality
which is naturally ordered to the good of spouses and the generation and education of
children. Moreover, it is a grave scandal when there is corruption of the young."
2396. "Among the sins gravely contrary to chastity are masturbation, fornication,
pornography, and homosexual practices."
