זוהר שמות — דף צה ע”א

Rabbi Hiya and Rabbi Yossi meet at the tower of Tyre and rejoice at their encounter. Rabbi Yossi recounts meeting an old merchant who posed difficult questions on the Torah and was revealed to be a sage upon whom the Shekhinah rested. The discussion addresses the laws of the Hebrew slave: six years symbolize the six supernal sefirot, and the seventh year symbolizes freedom. The soul descends to this world and must be liberated at the appointed time set by the Holy One blessed be He.