John Gills Exposition of the Bible Commentary - Proverbs 18:4
The words of a man's mouth are as deep waters ,.... The words of a great and mighty man; of an excellent and valuable man, as Jarchi; or of a wise man, as Aben Ezra. The doctrines which such a man has imbibed, and his heart is full of and his mouth utters, are like to "waters", pure, purifying, and refreshing; to "deep waters", which make no noise, and cannot be easily fathomed: such are the deep mysteries of grace, the wisdom of God in a mystery, spoken among them that are perfect; of... read more
Matthew Henry's Complete Commentary - Proverbs 18:4
The similitudes here seem to be elegantly transposed. 1. The well-spring of wisdom is as deep waters. An intelligent knowing man has in him a good treasure of useful things, which furnishes him with something to say upon all occasions that is pertinent and profitable. This is as deep waters, which make no noise, but never run dry. 2. The words of such a man's mouth are as a flowing brook. What he sees cause to speak flows naturally from him and with a great deal of ease, and freedom, and... read more