Manus manum lavat
Manus manum lavat (German: "One hand washes the [other] hand") is a Latin proverb. It is the translation of a verse by the Greek comedy poet Epicharm by Seneca in his satirical work Apocolocyntosis . There the continuation reads: "[...] give something and you get something."
A translation into German can be found in Goethe's poem Wie du mir, so ich dir : "Hand is only washed by hand, if you want to take, so give."
Nowadays, when using the proverb, the actual content term must be viewed more closely.
Trivia
In Cologne, in connection with the “ Kölsche Klüngel ” (you know each other and you help each other), another, very free translation of Manus manum lavat is known ; it reads: “One hand must not know who is washing the other”.
In a song of the same name by Saltatio Mortis , the " corruption and bungling" associated with this principle is criticized.