Charles Ellicott Commentary Judges 19:23

"And the man, the master of the house, went out unto them, and said unto them, Nay, my brethren, I pray you, do not so wickedly; seeing that this man is come into my house, do not this folly." — Judges 19:23 (ASV)

Do not commit this folly. —It is from no deficiency of moral indignation that the word “folly” (nebalah) is used. Sometimes, when a crime is too dark and deadly for ordinary reproach, the feelings are more deeply expressed by using a milder word, which is instantly corrected and intensified by the hearer himself. (Deuteronomy 22:21.) Thus, Virgil merely gives the epithet “unpraised” (“illaudati Busiridis aras”) to the cannibal tyrant, which serves even better than a stronger word. (Compare “Shall I praise you for these things? I praise you not” 1 Corinthians 11:17–22.) (See the author’s Brief Greek Syntax, p. 199.) This figure of speech takes various forms, including antiphasis, litotes, meiosis, etc.