כָּל־הַנְּחָלִים֙ הֹלְכִ֣ים אֶל־הַיָּ֔ם וְהַיָּ֖ם אֵינֶ֣נּוּ מָלֵ֑א אֶל־מְק֗וֹם שֶׁ֤הַנְּחָלִים֙ הֹֽלְכִ֔ים שָׁ֛ם הֵ֥ם שָׁבִ֖ים לָלָֽכֶת׃
All the rivers run into the sea, Yet the sea is not full; Unto the place whither the rivers go, Thither they go again.
Read halakhic rulings (Jewish law) on Ecclesiastes 1:7: and classical halakhic sources.