לַחֲכַם־לֵ֭ב יִקָּרֵ֣א נָב֑וֹן וּמֶ֥תֶק שְׂ֝פָתַ֗יִם יֹסִ֥יף לֶֽקַח׃
The wise in heart is called a man of discernment; And the sweetness of the lips increaseth learning.
Read kabbalistic (mystical) interpretation of Proverbs 16:21: and classical mystical sources.