14 Tie them as a sign on your forearm. Later Jewish tradition referred to the little leather containers tied to the forearms and foreheads as tefillin. They were to contain the following passages from the Torah: Exod 13:1–10, 11–16; Deut 6:5–9; 11:13–21. The purpose was to serve as a “sign” of covenant relationship and obedience.
15 Fasten them as symbols on your forehead. These were also known later as tefillin (see previous note) or phylacteries (from the Greek term). These box-like containers, like those on the forearms, held the same scraps of the Torah. It was the hypocritical practice of wearing these without heartfelt sincerity that caused Jesus to speak scathingly about them (cf. Matt 23:5).

In other versions

You shall bind them as a sign on your hand, and they shall be as frontlets between your eyes.

Tie them as symbols on your hands and bind them on your foreheads.

Bind them as a sign on your hand and let them be a symbol on your forehead.

Tie them to your hands and wear them on your forehead as reminders.

And you shall bind them as a sign on your hand, and they shall be as an emblem between your eyes.

And thou shalt bind them for a sign upon thine hand, and they shall be as frontlets between thine eyes.

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