13 No mortal comprehends its worth; it cannot be found in the land of the living.
13 Man knoweth not the price thereof; neither is it found in the land of the living.
13 Man does not know its worth, and it is not found in the land of the living.
13 Mortals don't have a clue, haven't the slightest idea where to look.
13 Man does not know its value, Nor is it found in the land of the living.
13 No one knows where to find it, for it is not found among the living.
Matthew Henry's Commentary on Job 28:13
Commentary on Job 28:12-19
(Read Job 28:12-19)
Job here speaks of wisdom and understanding, the knowing and enjoying of God and ourselves. Its worth is infinitely more than all the riches in this world. It is a gift of the Holy Ghost which cannot be bought with money. Let that which is most precious in God's account, be so in ours. Job asks after it as one that truly desired to find it, and despaired of finding it any where but in God; any way but by Divine revelation.