"... The terms “sign,” “reminder,” and “symbol” evoke some material object that serves to jog the memory, but they do not in themselves require a literal meaning for these verses. Rashbam actually considered the “deep, straightforward meaning” of the verses to be metaphorical. He adduced, in support, Song of Songs 8:6 ... Abraham Ibn Ezra mentions, but rejects, this figurative interpretation, which its proponents bolstered by citing additional biblical sources such as “For they are a graceful wreath upon your head, / A necklace about your throat” (Proverbs 1:9). “Let fidelity and steadfastness not leave you; / Bind them about your throat, / Write them on the tablet of your mind”. “Tie them over your heart always; / Bind them around your throat”. Other texts of the same order are Proverbs 7:3 as well as Jeremiah 17:1 and 31:32. Apparently, both the Samaritans and the medieval Jewish sect of Karaites also took the instructions of Exodus 13:9,16 metaphorically, for they do not have tefillin. Traditional rabbinic exegesis, however, interpreted Exodus 13:9,16 literally as enjoining the wearing of tefillin. This understanding is upheld by two other texts in the Torah that reiterate the precept. Deuteronomy 6:8, which is part of the section that has traditionally become known as the Shema, states: “Bind them [i.e., God’s teachings, v.6] as a sign on your hand, and let them serve as a symbol on your forehead.” A literal meaning is here favored by the immediately adjacent verse: “Inscribe them on the doorpost of your house and on your gates.” ..."