The concept of tikkun olam (תיקון עולם) or repairing the world through social action is one of the traditional categories of tzedakah (righteousness and justice). The word "tikkun" first appears in the book of Ecclesiastes (1:5; 7:13; 12:9), where it means "setting straight" or "setting in order." The most notable early rabbinic source for the phrase tikkun olam is the Aleinu prayer, where the phrase expresses the hope of repairing the world through the establishment of the kingdom of God.