Ecclesiastes 1:17
And I applied my heart to know wisdom and to know madness and folly. I perceived that this also is but a striving after wind.
Ecclesiastes 2:3
I searched with my heart how to cheer my body with wine--my heart still guiding me with wisdom--and how to lay hold on folly, till I might see what was good for the children of man to do under heaven during the few days of their life.
Ecclesiastes 1:13-14
And I applied my heart to seek and to search out by wisdom all that is done under heaven. It is an unhappy business that God has given to the children of man to be busy with.
Ecclesiastes 2:10-12
And whatever my eyes desired I did not keep from them. I kept my heart from no pleasure, for my heart found pleasure in all my toil, and this was my reward for all my toil.
Ecclesiastes 7:23-25
All this I have tested by wisdom. I said, "I will be wise," but it was far from me.
1 Thessalonians 5:21
but test everything; hold fast what is good.