Ecclesiastes 1:17
"And I gave my heart to know wisdom, and to know madness and folly: I perceived that this also is vexation of spirit."
Cross References (ranked by relevance)
Ecclesiastes 2:3
I sought in mine heart to give myself unto wine, yet acquainting mine heart with wisdom; and to lay hold on folly, till I might see what was that good for the sons of men, which they should do under the heaven all the days of their life.
1 Thessalonians 5:21
Prove all things; hold fast that which is good.