Proverbs 10:20

The tongue of the righteous is as choice silver, The heart of the wicked is worth little.

This chapter is full of proverbs about the tongue, speech and mouth.   It doesn't take much reading in Proverbs to realize that the wise have something good about their mouth, lips and tongue: Their Speech, and the foolish man has little value or worth in these items:  Their Speech.   The book of James tells us a lot about the tongue and most of James' teaching has its foundation in Proverbs.  In these two lines we see this contrast between the righteous and the wicked in regard to their speech.  The righteous, the wise person, has value in their tongue, their speech; like valuable, choice silver.  However, the heart of the wicked, the source for the tongue, has no worth ... and, therefore the tongue can produce nothing.   What Solomon is telling us is that the righteous has value in his/her heart and the tongue displays it.   However, the wicked has no value in his/her heart, so the tongue, therefore, has little value.   The heart is the well and the tongue is the bucket.   The bucket can only produce what is in the well.  Don't blame the tongue if it brings up bitter contents.   Don't praise the tongue if it simply carries the content of a heart made righteous by God.   What's in the well comes up in the bucket.