זוהר בראשית — דף קסב ע”א

Rabbi Yissa the Younger asks Rabbi Shimon about the verse “blessings upon the head of the righteous.” The answers are that the head is the holy crown; or Jacob, who received the blessings and poured them upon the righteous one, from whom they reach all the worlds; or the place of the covenant, from which the springs flow. One who guards the sign of the covenant and fulfills the commandments of the Torah is called righteous, and the blessings rest on his head and pass to his righteous children. Rabbi Yissa also asks about “I have been young, and now am old,” said by the prince of the world; the answer is that it is spoken within the holy union, and that the righteous one is held fast above and below. The passage ends with the question on “his seed begging bread.”