Real Wisdom is truly to know oneself and God, that is, that we are miserable and lost sinners and that God is merciful, not desirous of casting us away but eager to save us by grace for Christ's sake.
What Luther Says - #4696 - p. 1455
Those who have the Gospel have the wisdom of God and are wise in and from God. ... Wisdom...is the Gospel, and it teaches you to know God and the counsel of God in the Son of God, made flesh for you. This wisdom is hidden from the world; faith alone perceives it.
What Luther Says - #4697 - p. 1455