The heart of the wicked is little worth - כמעט kimat, is like little or nothing; or is like dross, while the tongue of the just is like silver. A sinner's heart is worth nothing, and is good for nothing; and yet because it is his most hidden part, he vaunts of its honesty, goodness, etc.! Yes, yes; it is very honest and good, only the devil is in it! that is all.
The tongue, the instrument of the mind is contrasted with the heart or mind itself, the just with the wicked, the choice silver with the worthless “little,” the Hebrew word being possibly taken in its primary sense as a “filing” or “scraping” of dross or worthless metal. If the tongue is precious, how much more the mind! If the heart is worthless, how much more the speech!