Musar zu Schemuel I 11:26

This אדמוני will eventually emerge purified and holy, a reference to the David who is also known as אדמוני. We read in Samuel I 16,12 that David is described as אדמוני עם יפה עינים וטוב ראי, "ruddy cheeked, bright-eyed and handsome." The first person to be described as אדמוני was Esau; it is therefore hardly a compliment to David to be similarly described. The essential difference is that whereas Esau was עין רע, represented all that is negative associated with the eye, David was the reverse, and is therefore described as יפה עינים. In David's case the positive aspects of eyes are meant: the prophet therefore describes him as טוב ראי. Solomon, who says in Kohelet 10,8: פורץ גדר ישכנו נחש, that "he who breaches the fence will be bitten by a snake,” may have referred to David's forbear Peretz, whom the Torah had described as "bursting out" (Genesis 38,29). The נחש referred to is the power of Esau. King Saul repaired the fence partially when he defeated נחש king of Ammon who went to war against Israel as reported in Samuel I 11,1. David also accomplished a great deal in this area during his reign. In the future, as the Messiah, however, he will take revenge on the forces of Esau in the manner of a serpent, as we know from Isaiah 14,29: כי משרש נחש יצא צפע, "For from the root of a snake there sprouts an asp."