A dire warning. The phrase comes from the Book of Daniel, in which the Persian king Belshazaar and his court see a disembodied hand appear during a feast and write on a wall, “Mene, Mene, Tekel u-Pharsin.” His seers unable to decipher the words, the king summons Daniel, who, keeping his interpretation streak intact: [see “
feet of clay”], reveals that the words refer to Belshazaar's reign and his kingdom being in jeopardy. And sure enough, later that evening the king was murdered and his kingdom given to the Medes, just as Daniel had predicted. “The handwriting on the wall” or “the writing on the wall” came to refer to any prediction or omen that a venture was doomed to failure.