The Tefillin of the arm has one chamber. The four different Torah texts that go into the head tefillin are written on one roll of parchment and inserted into the tefillin of the arm. This Tefillin is positioned on the arm from the chest/heart level and the strap continues down to the palm of the hand and represent the Sefirot of Tiferet, Netzach, Hod and Yessod that connect the light to Malchut.
Moses asked God to reveal himself to him but God said that he can’t because no man can see him and live. The reason for that is that the revelation of God would nullify all material existence. God did agree to show Moses his back.
“וְהָיָה בַּעֲבֹר כְּבֹדִי וְשַׂמְתִּיךָ בְּנִקְרַת הַצּוּר וְשַׂכֹּתִי כַפִּי עָלֶיךָ עַד עָבְרִי.”
“וַהֲסִרֹתִי אֶת כַּפִּי וְרָאִיתָ אֶת אֲחֹרָי וּפָנַי לֹא יֵרָאוּ”
“and it will come about, while My glory is passing by, that I will put you in the cleft of the rock and cover you with My hand until I have passed by.”
“”Then I will take My hand away and you shall see My back, but My face shall not be seen.”
The Zohar mentions here the teaching of the sages that God showed Moses the knot of his Tefillin. We studied previously DZ 2494 https://dailyzohar.com/daily-zohar-2494/) that God wears Tefillin. The knot of the head tefillin should be positioned at the base of our skull to represent the connection to Da’at that delivers the Light from the ‘head’ to the lower levels. Moses achieved the level of Da’at and could connect to God directly and benefit us with his level. He could bring us the Torah from the upper levels and the knowledge of the oral Torah that is in the Talmud and the Zohar.
Moses is the Faithful Shepherd that is mentioned many times in the Zohar.
“Not so, with My servant Moses, He is faithful in all My household;”
Daily Zohar # 2498 – Vaetchanan – The servant in God's household