Beware of the dog
Beware of the dog is a warning sign posted at the entrance to a building or other private area indicating that a dangerous dog is within. Such signs may be placed to deter burglary even if there is no dog, or if the dog is not actually a competent guard dog.
History
Warning signs of this sort have been found in ancient Roman buildings such as the House of the Tragic Poet in Pompeii, which contains a mosaic with the caption . The Roman work Satyricon, written by Petronius, includes a passage mentioning the phrase painted on a wall with large letters, in the chapter Dinner with Trimalchio.Philippians 3:2 is translated as "beware of the dogs" or "beware of dogs" in the King James Bible and many other editions. For example:
This is often interpreted as a euphemism, bad people having been described as dogs in a number of previous biblical passages. Nonetheless, the yard signs are sometimes alluded to in reference to the passage. The use of such signs in the Roman world may have influenced the author of the passage, and conversely the passage may have influenced the wording of the more modern yard signs.