Commentary for Ecclesiastes 1:4

A generation passes away and [another] generation comes. As much as the wicked man toils and labors to oppress and to rob, he does not outlive his activities, for the generation passes on and another generation comes and takes away everything from his sons, as the matter is stated, “His children must appease the poor.”²²Iyov 20:10.

“One generation passes, and one generation comes; and the earth abides forever. The sun rises and the sun sets, and hastens its place where it rises” (Ecclesiastes 1:4–5).
“One generation passes, and one generation comes” – Rabbi Yudan says in the name of Rabbi Levi: There is no day on which six hundred thousand are not born and on which six hundred thousand do not die. What is the reason? “One generation passes, and one generation comes…the sun rises and the sun sets.” Rabbi Berekhya, Rabbi Yaakov bar Avuna, and Rabbi Ḥiyya bar Abba [said] in the name of Rabbi Levi bar Sisi: From when the sun rises until the sun sets, one generation passes, and one generation comes. From where is it derived that a generation consists of six hundred thousand? It is as it is stated: “If any man among these people, this wicked generation” (Deuteronomy 1:35), and that generation consisted of six hundred thousand. Rabbi Berekhya said: [When a] potter places [vessels] into the furnace, what he places first [he removes] last. However here, one who passes first comes first, and one who passes last comes last.¹⁸The reference here is to death and the revival of the dead.

And the earth abides forever. But who are the ones who [cause the earth to] endure? The humble and low, who bring themselves down to the ground, as the matter is stated, “But the humble shall inherit the earth.”²³Tehillim 37:11. ²⁴Alternatively, unlike generations, that when one passes by, another one comes, the earth does not change. But Midrash Tanchuma states, that all the righteous of Yisroel are called earth [=אֶרֶץ, as it is stated, “for you will be a desirable land.”²⁵Malachi 3:12.