The old saying, let sleeping dogs lie, means more than just to let sleeping dogs lie, which is very sound advice in the first place. It also means that one ought not instigate trouble. In other words, people should leave situations or people alone else it might cause them trouble.
The Atlanta Constitution newspaper reported on a court case on August 6, 1909 that dealt with a Mr. Jerome who had menaced a Mr. Carvalho who had threatened Mr. Jerome. The article read in part:
“You’d better let sleeping dogs lie, Mr. Jerome,” exclaimed the witness, before the district attorney had said a word. As he spoke the expert’s eyes flashed and he pointed an agitated finger at Jerome.
In November of 1870, the New York Times ran an article entitled, “Russia and India: The Frontier of the Russian Empire.” The article asked whether England was on the verge of losing its Asiatic possessions.
Let us consider why Russia has gained enough to suppose she is sufficiently strong to infringe the wholesome rule to “let sleeping dogs lie” when applied to the English. The Crimean War showed her plainly that her people were barbarians, and that her strength lay in brute force.
The saying “let sleeping dogs lie” was a favourite of Sir Robert Walpole, the first Prime Minister of Great Britain, who exercised considerable influence over King George I as well as King George II from 1721 through to 1742. He was quoted as saying this on more than one occasion regardless of whether it had to do with matters of the King’s Court, the American Revolution or any other situation where difficulties had arisen.
Geoffrey Chaucer used a similar phrase in his story, Troilus and Criseyde, published in 1374.
It is nought good a sleepyng hound to wake.
It’s recorded in French even earlier in the 14th century, as found in the Proverbia Vulgalia et Latina, where the saying is: “Ne reveillez pas le chien qui dort.” Translation: Do not wake the dog that sleeps.
As the phrase is referenced in the Proverbia Vulgalia et Latina, it is most likely that it comes from the Latin saying, “Quieta non movere” which means “Do not move settled things.”
That being said, the Book of Proverbs (26:17) says:
He that passes by, and meddles with strife belonging not to him, is like one that takes a dog by the ears.
In other words, the saying “let sleeping dogs lie” has its roots in the Bible.
Historically Speaking 