Ecclesiastes 7:23

Also take no heed unto all words that are spoken; lest thou hear thy servant curse thee:

For oftentimes also thine own heart knoweth that thou thyself likewise hast cursed others.

That which is far off, and exceeding deep, who can find it out?

I applied mine heart to know, and to search, and to seek out wisdom, and the reason of things, and to know the wickedness of folly, even of foolishness and madness: