Let them not depart from thine eyes; keep them in the midst of thine heart.
– Proverbs 4:21
Solomon continues addressing the sensory parts here with eyes and heart. The eyes see and read the words of wisdom that are written. The eyes are also put for looking well to your goings, which is a crucial feature of wisdom. The heart often means the mind or thinking faculty. It can also refer to the emotions or the whole inner being. Wise sayings must be fixed in the mind which speaks to deliberate actions rather than heat-of-the-moment decisions.