יָדַ֕עְתִּי כִּ֛י אֵ֥ין ט֖וֹב בָּ֑ם כִּ֣י אִם־לִשְׂמ֔וֹחַ וְלַעֲשׂ֥וֹת ט֖וֹב בְּחַיָּֽיו׃
I know that there is nothing better for them, than to rejoice, and to get pleasure so long as they live.
Read midrashic interpretation of Ecclesiastes 3:12: and classical rabbinic exegesis.