The Letter of St. James is perhaps best known nowadays for verse 2:17, "So also faith of itself, if it does not have works, is dead." (Odd, though perhaps a sign of hope, that verse 2:20 isn't the standard apologetical proof text.)
There's a less celebrated parallel between St. James's notions of faith and wisdom:
Indeed someone might say, "You have faith and I have works." Demonstrate your faith to me without works, and I will demonstrate my faith to you from my works. [2:18b]
Who among you is wise and understanding? Let him show his works by a good life in the humility that comes from wisdom. [3:13]
Just as faith without works is dead, so too is wisdom without works.
And wisdom is what, exactly?
I remember reading the Book of Wisdom, in particular the extended praise of Wisdom in chapters 7-10, and thinking, "It's nice that Wisdom is wonderful and all, but the fellow neglected to mention what it is." Looking again, I find that I was not quite right about that:
[Wisdom] is an aura of the might of God and a pure effusion of the glory of the Almighty; therefore naught that is sullied enters into her. For she is the refulgence of eternal light, the spotless mirror of the power of God, the image of his goodness.
I suspect the first time I read this I took it as more of the poetical praise of Wisdom that comes earlier in the chapter. Now, I suspect, this is about as good a definition as you're likely to get.
There is the Wisdom that is God Himself, the Wisdom that is Love that is Justice that is Truth that is Goodness that is Beauty. From the Godhead comes the divine Wisdom that is the aura of the might of God, the spotless mirror of His power. This image of God's goodness is to God as sunlight is to the sun; it's what we see when we look toward God. We might say this divine Wisdom is the sight of God at work.
...wisdom denotes a certain rectitude of judgment according to the Eternal Law.
The Eternal Law is divine Wisdom; perceiving this Wisdom, the wise act according to it, like a dancer following her partner's lead.
I don't think we need to settle for the tautology that acting according to divine Wisdom is wise. Divine Wisdom itself is acting according to God's love for us. To be wise, then, to employ the gift of wisdom, is to turn to face God and receive that love, and that -- quite apart from commandments and legalities -- is always the right and good thing.