Ecclesiastes 7:12

The comparison is unusually fair to money, which is why it is worth trusting.

Wisdom is a defense, even as money is a defense. The Preacher does not pretend that wealth is useless. It genuinely shelters people — from small crises, from bad luck, from the consequences of one mistake. Anyone who has been without it knows this. A book that denied it would not be worth reading on this subject.

So both are defenses, and the word suggests a shadow or shade: something you stand under, which blocks what would otherwise fall on you. Both work. That much is conceded.

The difference comes in the second half, and it is a difference in kind rather than degree. Wisdom preserves the life of him who has it. Money shelters your circumstances; wisdom keeps the person. One protects what you have. The other protects what you are.

That distinction shows up most clearly in how the two behave under loss. A person whose defense was money and who loses it has lost the defense. A person whose defense was wisdom and who loses everything else still has it — and Ecclesiastes, a book preoccupied with the fact that everything is eventually lost, is exactly the place you would expect that argument to be made.

The excellency of knowledge is a phrase about surplus. It does something the other cannot.