Knowledge is very useful, utilitarian; wisdom is absolutely useless, but that's its beauty. It is not a commodity, you cannot use it in any way; you cannot sell it, you cannot purchase it. It does not belong to the utilitarian world; it is a flowering.
What use is a rose flower? What use is the song of a bird? What use is it? If you look around in existence -- the stars, the clouds, the mountains, the rivers -- what is the use of it all? It is all useless. Why are butterflies so beautiful? Why does God take so much care in painting their wings? What is the point of it all?
Remember, the outside world is the world of utility; the inside world is the world of significance, not of utility. The outside world has a totally different dimension -- there it is needed. You need bread, you need butter, you need a house, you need medicine, you need clothes, shelter; you need thousands of things. But the inner world is simply of luxury; it is not a need, it is a joy. It is a sheer rejoicing.