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 halakhic rulings (Jewish law) on Ecclesiastes 3:12 from the Mishneh Torah and classical halakhic sources, free online.