And you shall bind them for a sign on your hand; and they shall be for frontlets between your eyes. Deuteronomy 6:8
Sign – What do Exodus 4:8, Jeremiah 32:20, I Samuel 2:34 and Isaiah 20:3 have in common with binding tefillin on the arm and the head? Maybe we should start with the question: What are tefillin? The use of tefillin is considered by orthodox Jews to be one of the most important mitzvot (obligations) of Torah. Tefillin are two small leather boxes attached to leather straps. Each box contains four sections of Scripture (The Shema of Deuteronomy 6:4-9, the Vehayah of Deuteronomy 11:13-21, the Kadesh of Exodus 13:1-10 and the Vehayah of Exodus 13:11-16). These four sections of Scripture are crucial in identifying the people God chose and the obligations they accepted. These boxes are bound to the arm and the head. You can see what this looks like here.
What does a small leather box have to do with these other Scripture references? If you look them up, you won’t find anything about boxes. But you will find the Hebrew word ‘ot, the word for “sign.” What you need to know is that ‘ot is most often the word for God’s awe-inspiring events and miracles; signs of His sovereignty over all men and their history. So, tefillin might be boxes but their purpose is to act as reminders of who God is, seen in His mighty acts of power. That little box suspended from the arm and tied to the head is designed to never let us forget what God did to rescue us and make us His own people.
Christians have universally substituted other icons for tefillin. These are usually symbols of the cross, the nails or some saint. I don’t believe I have ever seen a Christian with tefillin bound to his arm. And while it is true that a cross hung around the neck reminds us of the death of our Messiah, don’t you find it a bit curious that there is never any mention at all in Scripture (even in the New Testament) about a sign of the cross. Since we know that Paul was a practicing Torah-observant Jew, we know that he bound tefillin to his arm and his head. But he didn’t wear a cross on a silver chain. In fact, the only place in the entire Bible where some kind of symbolic emblem is part of the instructions of living is here, with tefillin. There must be a very good reason why God wants us to remember His mighty deeds. Perhaps Heschel is right: “To believe is to remember.”
We should also notice that there are no artistic representations of God in Judaism. There are reminders of His acts, but there are no paintings, icons, drawings or any other physical representations of Him. Have you ever wondered why? Our contemporary Christian world is not only filled with alternative signs, it is also saturated with iconic and artistic representations. Michelangelo even painted God on the ceiling. What happened in the transition from the Jewish Messianic assemblies of the first century to the church of the third century that allowed an artistic expression that never occurred in the previous sixteen hundred years? And why are we so accustomed to these expressions today that we don’t even reflect on their total absence in Scripture? Do you suppose that we have stopped remembering? Do you suppose that we have substituted imagery for the living God?
“The primary function of symbols is to express what we think; the primary function of the mitzvot is to express what God thinks. Religious symbolism is a quest for God, Jewish observance is a response to God.”
Topical Index: sign, tefillin, Deuteronomy 6:8
 Abraham Heschel, Spiritual Audacity and Moral Grandeur, p. 92.