"      Sin is a personal act. Moreover, we have a responsibility for the sins committed by others when we cooperate in them: - by participating directly and voluntarily in them; - by ordering, advising, praising, or approving them; - by not disclosing or not hindering them when we have an obligation to do so; - by protecting evil-doers. Thus sin makes men accomplices of one another and causes concupiscence, violence, and injustice to reign among them. Sins give rise to social situations and institutions that are contrary to the divine goodness. "Structures of sin" are the expression and effect of personal sins. They lead their victims to do evil in their turn. In an analogous sense, they constitute a "social sin."
                                                                                                                                                                                                                                                              "                                                - Catechism of the Catholic Church, 1868-1869

"wherever there occurs a special kind of deformity whereby the venereal act is rendered unbecoming, there is a determinate species of lust. This may occur in two ways: First, through being contrary to right reason, and this is common to all lustful vices; secondly, because, in addition, it is contrary to the natural order of the venereal act as becoming to the human race: and this is called "the unnatural vice." This may happen in several ways. First, by procuring pollution, without any copulation, for the sake of venereal pleasure: this pertains to the sin of "uncleanness" which some call "effeminacy." Secondly, by copulation with a thing of undue species, and this is called "bestiality." Thirdly, by copulation with an undue sex, male with male, or female with female, as the Apostle states (Romans 1:27): and this is called the "vice of sodomy." Fourthly, by not observing the natural manner of copulation, either as to undue means, or as to other monstrous and bestial manners of copulation" - Aquinas, Summa Q. 154, Article 11

"Perdition is the end that awaits them, their own hungry bellies are the god they worship, their own shameful doings are their pride; their minds are set on the things of earth" - Philippians 3:19

"The gaming table is evil and the trap of an enemy who does not confer wealth but rather takes it all away. It makes people poor, destroys their wealth, forces them into debt, robs them of their inheritance without legal proceedings of any sort." - De Aleatoribus, St. Cyprian

"For if we do it with wrath, it no longer seems to be the boldness (of one who is confident of his cause,) but passion: but if with gentleness, this is boldness indeed. For in one and the same thing success and failure cannot possibly go together. The boldness is a success: the anger is a failure. Therefore, if we are to have boldness, we must be clean from wrath that none may impute our words to that. No matter how just your words may be, when you speak with anger, you ruin all: no matter how boldly you speak, how fairly reprove, or what not" - St John Chrysostom

“Envy is the form of hatred that is the hardest to tame.  While acts of kindness may soothe those who might otherwise be our enemies, this same kindness shown to the envious and malicious person irritates him even more.  The more he is shown kindness, the more indignant and displeased and disgusted he becomes.” - St. Basil

"Pride goeth before destruction: and the spirit is lifted up before a fall." - Proverbs 16:18