11 Let us then discern the snares, and walk far off from them! Let us discern the precipices, and not even approach them! This will be the foundation of our greatest safety not only to avoid things sinful, but those things which seem indeed to be indifferent, and yet are apt to make us stumble towards sin. For example; to laugh, to speak jocosely, does not seem an acknowledged sin, but it leads to acknowledged sin. Thus laughter often gives birth to foul discourse, and foul discourse to actions still more foul.
Often from words and laughter proceed railing and insult; and from railing and insult, blows and wounds; and from blows and wounds, slaughter and murder. If, then, you would take good counsel for yourself, avoid not merely foul words, and foul deeds, or blows, and wounds, and murders, but unseasonable laughter, itself, and the very language of banter; since these things have proved the root of subsequent evils. Therefore Paul says, “Let no foolish talking nor jesting proceed out of your mouth.” For although this seems to be a small thing in itself, it becomes, however, the cause of much mischief to us.
Again, to live in luxury does not seem to be a manifest and admitted crime; but then it brings forth in us great evils—drunkenness, violence, extortion, and rapine. For the prodigal and sumptuous liver, bestowing extravagant service upon the belly, is often compelled to steal, and to seize the property of others, and to use extortion and violence. If, then, you avoid luxurious living, you remove the foundation of extortion, and rapine, and drunkenness, and a thousand other evils; cutting away the root of iniquity from its extremity.
Hence Paul says, that “she who lives in pleasure is dead while she lives.” Again, to go to the theatres, or to survey the horse-race, or to play at dice, does not seem, to most men, to be an admitted crime; but it introduces into our life an infinite host of miseries. For spending time in the theatres produces fornication, intemperance, and every kind of impurity. The spectacle of the horse-race also brings about fightings, railings, blows, insults, and lasting enmities. And a passion for dice-playing has often caused blasphemies, injuries, anger, reproaches, and a thousand other things more fearful still.
Source: Homilies on the Statues (New Advent)