For it is written, I will destroy the wisdom of the wise, and will bring to nothing the understanding of the prudent.
I will destroy - slightly altered from the Septuagint, Isaiah 29:14. The Hebrew is, 'The wisdom of the wise shall perish, and the understanding of their prudent men shall be hid.' Paul, by inspiration, gives the sense of the Spirit, by making God the cause of their wisdom perishing, etc., "I will destroy," etc.
Understanding of the prudent - literally, of the understanding ones.