Pro 3:1-5 My son, do not forget my teaching, but let your heart keep my commandments, (2) for length of days and years of life and peace they will add to you. (3) Let not steadfast love and faithfulness forsake you; bind them around your neck; write them on the tablet of your heart. (4) So you will find favor and good success in the sight of God and man. (5) Trust in the LORD with all your heart, and do not lean on your own understanding.
I’ve written about this passage before asking whether or not it was promoting a form on non-deliberative mysticism.
Another question to ask is this: is the author saying that the young man, “my son,” should never lean on his own understanding?
I think the answer is no. “My son” is clearly among the simple, a group of characters in Proverbs who have the potential to become wise but are in danger of seeking folly instead.
The young man who seeks wisdom in Proverbs ultimately becomes a man of understanding:
Pro 3:13-14 Blessed is the one who finds wisdom, and the one who gets understanding, (14) for the gain from her is better than gain from silver and her profit better than gold.
Pro 5:1-2 My son, be attentive to my wisdom; incline your ear to my understanding, (2) that you may keep discretion, and your lips may guard knowledge.
Pro 14:29 Whoever is slow to anger has great understanding, but he who has a hasty temper exalts folly.*
The stage of life in which one has no understanding is one in which one must rely on the commands of God (that doesn’t change) and the wisdom of teachers. But eventually one must gain the understanding necessary to navigate life in the case of circumstances for which there is no direct command from God or in which there are no mentors.
*In the passages cited, there are two different Hebrew words being translated “understanding,” but they are near synonyms.