Fifth Lateran Council on Impurity
The Fifth Lateran Council decrees: That clerics may live chastely and continently as required by the sacred canons, we decree that those who do contrary be severely punished. If anyone, cleric or layman, be convicted of the crime on account of which the anger of God came upon the children of unbelief, let him be punished in accordance with the sacred canon or the civil law respectively. Concubinarii, whether clerical or lay, shall be punished in accordance with the same canons. Toleration by superiors, contrary custom, or any other subterfuge cannot be accepted as justifiable excuses; these must be corrected and those who tolerate them punished in accordance with the law.
For know you this and understand: That no fornicator or unclean or covetous person (which is a serving of idols) hath inheritance in the kingdom of Christ and of God. Let no man deceive you with vain words. For because of these things cometh the anger of God upon the children of unbelief. (Ephesians 5:5-6)
Mortify therefore your members which are upon the earth: fornication, uncleanness, lust, evil concupiscence and covetousness, which is the service of idols. For which things the wrath of God cometh upon the children of unbelief. (Colossians 3:5-6)