Dear Ralph,

It is evident from the Gemara that Jews did wear Tefilin in the Midbar. The Gemara asks why the Torah mentions coming to Eretz Yisrael at the beginning of the section with Tefilin. The answer is given that the Torah means to say, "Do the Mitzvah of Tefilin, and in its merit you will deserve to enter Eretz Yisrael."

(Some point out that two of the four Torah portions which are wrapped in the Tefilin were given only after 40 years in the desert. From this they conclude that the original Tefilin worn in the desert had only two portions. The other two were added to Tefilin only at the end of the 40 year stay in the desert.)

All the best,

Reuven Weiner