“God spoke to Moses, saying: Speak to the Israelites and have them bring Me an offering. Take My offering from everyone whose heart impels him to give.”
“Take for me an offering...” hints to the Tefillin. There are three levels in the secret of Tefillin. The first is the Tefillin worn on the head, the second – on the arm, and the third one is the knot of the head Tefillin.
The two boxes of the Tefillin correspond to the two Temples that have already existed. Their place on the man's body is where "the kings", or the controllers are, that is, the heart and the brain. About the Tefillin the Torah said, “And the people of the world will see that the Name of God is written on you, and they will fear you,” and about the Temple the Torah said, “You should fear my holy place, the Temple.”
Corresponding to the three levels of Tefillin, the Jews brought three different offerings (Terumah). The hints to this are found in the spelling of the offerings' description, and it also helps understand the greatness of the Tefillin themselves.
Art: Carl Haag - A Jerusalemite Shepherd Winding the Phylacteries for the Hand