Solomon as Kohelet explains the "Unhappy Business of God"

"Biblia Sacra #54 - Vanitas Vanitatum", 1969 Lithograph, by Salvadore Dali.

In this painting we find King Solomon, Kohelet (Sage, Preacher), bedecked in all his finery, pointing his finger to the sky.  This lithograph was created by Salvadore Dali in response to Solomon's proclamation that all is vanity.

ESV Study Bible Devotions

Ecclesiastes 1:12-18 - I the Preacher have been king over Israel in Jerusalem. 13 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. 14 I have seen everything that is done under the sun, and behold, all is vanity and a striving after wind.

15 What is crooked cannot be made straight,
and what is lacking cannot be counted.

16 I said in my heart, “I have acquired great wisdom, surpassing all who were over Jerusalem before me, and my heart has had great experience of wisdom and knowledge.” 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.

18 For in much wisdom is much vexation,
and he who increases knowledge increases sorrow.

Here are a few things that wise Solomon desires that we understand:

• Try as we may, the natural mind will never understand all the things of God.  God's mind is infinite, while our minds are clearly finite.  The difference between the two is incomprehensible.  Therefore, some things of God are simply going to be unknown to us, and must be labled as mystery.  Anything else is simply attempting to catch the wind in your hands.  Absolutely impossible.
• When you do apply all the wisdom you have, you will end at a mighty infinite chasm staring with sorrow, as you realize that the "unhappy business of God" is our eternal separation from God.  We are born fallen, dead, separate from God.  "What is crooked cannot be made straight".

The simple truth of the matter is that without acquiescence to Solomon's findings, we can never fully know God.  As long as we in our foolish pride strive to catch the wind, the end result will be madness, folly, and ultimately eternal separation from God.

For some unknowable reason, God has ordained that we endure hardships in our present fallen state.  Why did God ordain evil, pain, hardship?  We cannot search the depth of the infinite mind of God.  We simply are not completely told.

Thankfully, God has provided a way out of this eternal separation.  Although we endure pain, and suffering, here on earth, this is temporary, a vapor, a puff of smoke, in light of eternity.

From Jesus Christ, in Luke 19:10 - "For the Son of Man came to seek and to save the lost.”