Proverbs 6:13. He speaketh with his feet, he teacheth with his fingers.
Feet and fingers are frequently used in the East as a means of communicating ideas, especially when in the presence of those from whom it is intended to conceal the information imparted, and who might hear if words were uttered. Certain movements of hands and feet are understood to have a definite meaning, so that merchants have been known to bargain in the presence of others by sitting on the ground with a piece of cloth thrown over the lap, under which they arrange their terms by the movements of their fingers. In a similar way the Brahmins convey religious mysteries to their disciples, their hands being concealed in the folds of their robes. Thus they teach “with their fingers.” See also John 13:24.
Debauchees and dancing girls are in the habit of making gestures and movements with their feet. Some suppose Solomon to refer to these when he speaks of the “naughty person” as he does in the text. The practice was known among the ancient Romans and is described by classic authors.