Rabbi Elazar tells of the supernal source of the four Mochin in the head of Zeir Anpin that correspond to the four paragraphs in the four compartments of the Tefilin. The rabbis talk about the whole flow of mercy and supernal light; the Holy Name Yud Hei Vav Hei and the various Sfirot are brought in to illuminate the discussion. We learn about the four pillars of the Chariot, that are the three Patriarchs and David. Rabbi Yitzchak says that God will not enter celestial Jerusalem until His people enter terrestrial Jerusalem. He also talks about testimony, that is the flowing of the illumination of Chochmah from supernal Eden.