John Chrysostom, On the Statues
, Homily 15.4 (tr. W.R.W. Stephens):
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.
τὸ γελᾷν καὶ ἀστεῖα λέγειν οὐ δοκεῖ μὲν ὡμολογημένον ἁμάρτημα εἶναι, ἄγει δὲ εἰς ὡμολογημένον ἁμάρτημα· πολλάκις γοῦν ἀπὸ γέλωτος αἰσχρὰ ῥήματα τίκτεται, ἀπὸ ῥημάτων αἰσχρῶν πράξεις αἰσχρότεραι· πολλάκις ἀπὸ ῥημάτων καὶ γέλωτος λοιδορία καὶ ὕβρις, ἀπὸ λοιδορίας καὶ ὕβρεως πληγαὶ καὶ τραύματα, ἀπὸ τραυμάτων καὶ πληγῶν σφαγαὶ καὶ φόνοι.
ἄν τοίνυν μέλλῃς περὶ σεαυτοῦ καλῶς βουλεύεσθαι, οὐχὶ τὰ αἰσχρὰ ῥήματα μόνον, οὐδὲ τὰ αἰσχρὰ πράγματα, οὐδὲ τὰς πληγὰς καὶ τὰ τραύματα καὶ τοὺς φόνους, ἀλλὰ καὶ αὐτὸν τὸν ἄκαιρον γέλωτα καὶ αὐτὰ τὰ ἀστεῖα ἀποφεύξῃ ῥήματα, ἐπειδὴ τῶν μετὰ ταῦτα κακῶν ῥίζα ταῦτα ἐγένετο.
This ("laughter often gives birth to foul discourse, and foul discourse to actions still more foul," etc.) is a good example of the rhetorical device known as climax or gradatio. For other examples see: