זוהר שמות — דף לט ע”א

Solomon was called by seven names, and Kohelet encompasses them all. He composed three books: Song of Songs for Hesed, Kohelet for judgment, Proverbs for mercy — to complete Wisdom. The secret of hevel (breath) is precious: it is the breath from the mouth that becomes a voice. The world subsists only through the breath of innocent schoolchildren. The righteous perish when this breath draws from judgment; the wicked prosper when it draws from mercy — everything depends on this hevel.