On the lips of him who has understanding, wisdom is found,
but a rod is for the back of him who lacks sense.
Wisdom begins with revelation from the Lord. Wisdom, like revelation, comes from above, not below (see James 3:13-18, which speaks of "wisdom from above"). Satan's temptation to rebellion in the garden involved the substitution of wisdom from below for the wisdom from above (Genesis 3:4-5). In order to gain understanding about truth and reality, revelation from God is the starting point, not our reason or our own understanding (Proverbs 3:5). Proverbs way of saying this is that the fear of the Lord is the beginning of wisdom (Proverbs 1:7, 9:10). Jesus' way of saying this is that the wise man must build his life on his words or revelation:
"Everyone then who hears these words of mine and does them will be like a wise man who built his house on the rock. . . . And everyone who hears these words of mine and does not do them will be like a foolish man who built his house on the sand" (Matthew 7:24, 26 --- notice how Jesus viewed his words as authoritative and revelation from above).
The person of "understanding" is the person who "can distinguish wrong from right, good from bad, better from best." He can do this because "he has, though practice in applying God's word, learned to discern God's way in this world (Hebrews 5:14)."
In order to speak wisdom to others, we must listen to the Lord. The better we listen to Christ, the more wisely we will speak to others. Only the teachable can teach. Only those, who like Mary, have sat at Jesus' feet listening and applying the Lord's words to themselves, will prepare themselves to speak wisely to others.
Derek Kidner has entitled this proverb: "God's mouthpiece or God's mule." This is because the proverb teaches that if we won't be guided by God's Word, then we will have to be guided by the Lord's force. In this title, Kidner is making an allusion to Psalm 32. The wise are privileged to have the Lord as their teacher:
"I will instruct you and teach you in the way you should go;
I will counsel you with my eye upon you" (v. 8).
But the wicked, because they refuse to listen to the Lord, must be sovereignly guided and dealt with through force --- "a rod is for the back of him who lacks sense":
"Be not like a horse or a mule, without understanding,
which must be curbed with bit and bridle,
or it will not stay near you" (v. 9)
No wonder, then, that the sorrows of the wicked are many, for force is far more unpleasant than instruction:
"Many are the sorrows of the wicked,
but steadfast love surrounds the one who trusts in the Lord" (v. 10).
The fool, "who lacks sense" earns his punishment by his refusal to listen to the Lord and put his words into practice. That punishment will come suddenly in final disaster, as our Lord Jesus Christ makes plain:
"And everyone who hears these words of mine and does not do them will be like a foolish man who built his house on the sand. And the rain fell, and the floods came, and the winds blew and beat against that house, and it fell, and great was the fall of it" (Matthew 7:26-27).