זוהר בראשית — דף רד ע”א

The Zohar continues with Rabbi Yitzhak and asks what the “days of evil” are: not the days of old age, but days arising from the creation of the world through the letters. The letter Tet struggled to join the letter of evil until the Holy One, blessed be He, separated them and created days of good, on the right side, and days of evil, on the left; these are also called years of plenty and years of famine. According to the secret, Joseph, during the famine year, sealed the spring of the covenant so as not to give place to the side of impurity, and one who does not guard himself so is said to bear “strange children.” A person must hope in the Lord; happy are the righteous who walk in His ways. When this side rules, one should not appear in the marketplace, as Jacob did not.