Yetzer is the inclination towards either good or evil in Judaism. Yetzer HaTov is the inclination towards good and Yetzer HaRah is the inclination towards evil.
According to Judaism, human beings have a dual nature. Humanity is neither fundamentally good nor evil but had a tendency in both directions. Judaism teaches that by doing good, or by overcoming temptation to do evil, humans prove their value to God.
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Yetzer harah
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