The mouth of a righteous man is a well of life - חיים מקור mekor chaiyim, is the vein of lives; an allusion to the great aorta, which conveys the blood from the heart to every art of the body. The latter clause of this verse is the same with that of Proverbs 10:6.
Compare Proverbs 10:6. Streams of living water (like the “fountain of living waters” of Jeremiah 2:13; Jeremiah 17:13, and the “living water” of John 4:10), flow from the mouth of the righteous, but that of the wicked is “covered,” i. e., stopped and put to silence by their own violence.