Judaism affirms that people are born with both a "yetzer ha-tov" (יצר הטוב), an inclination or impulse to do good, and with a "yetzer hara" (יצר הרע), an inclination or impulse to do evil. These phrases reflect the concept that "within each person, there are opposing natures continually in conflict" and are referenced many times in the rabbinic tradition. The rabbis even recognize a positive value to the "yetzer ha-ra": without the "yetzer ha-ra" there would be no civilization or other fruits of human labor. Midrash (Bereshit Rabbah 9:7) states: "Without the evil inclination, no one would father a child, build a house, or make a career." The implication is that "yetzer ha-tov" and "yetzer ha-ra" are best understood not only as moral categories of good and evil, but as the inherent conflict within man between selfless and selfish orientations.