Commentary for Ecclesiastes 8:17

And I saw all the works of God. That He gave over to mankind.

“I saw all the work of God, as man is unable to discover the work that is performed under the sun. Although man toils to seek, he will not find; even if a wise man will wish to know, he will not be able to find” (Ecclesiastes 8:17).
“I saw all the work of God.”⁴⁶This is understood as a reference to mitzvot. The continuation of the verse indicates that man will never understand everything about Torah and mitzvot. Rabbi Pinḥas and Rabbi Yirmeya [said] in the name of Rabbi Ḥiyya bar Abba: Many sought to perform and fathom the Torah, but were unable to do so. What is the reason? “Although man toils to seek, he will not find.” “Even if a wise man will wish” – this is Solomon on the day that he said: I am able to amass⁴⁷Many wives. without straying.⁴⁸He did so despite it being contrary to the verse: “He shall not amass wives, and his heart will not stray” (Deuteronomy 17:17).
Rabbi Yehoshua of Sikhnin said in the name of Rabbi Levi: It is written: “Who renders princes into nothing” (Isaiah 40:23) – this is Moses. At the moment that he said: “The matter that is too difficult for you, [bring to me and I will hear it]” (Deuteronomy 1:17), the Holy One blessed be He said to him: ‘Moses, you judge the difficult [cases]? I will bring you a case that the disciple of your disciple can judge, and even women, but you will be unable to resolve it.’ Which [case] is that? This is the case of the daughters of Tzelofḥad. The Rabbis say: God forbid; Moses was not arrogant. Rather, this is what he said: “The matter that is too difficult for you” – if I have clear knowledge of it, “I will hear it.” If not, I will refer it to God.

That man cannot discover, etc. Mankind is unable to fathom the ways of the Holy One, Blessed Is He, what the reward is for all the work that is done under the sun, for they see wicked men prospering and righteous men declining.