"G‑d would walk in front of them by day….and at night in a pillar of fire to provide light.." (Ex. 13:21)

The light that G‑d provided for the Israelites during the entire forty years in the desert never departed from the camp of the Israelites, as our Sages explained. (Shabbat 22) However, it never extended beyond the boundaries of that camp either, and for good reason.

...outside their camp it was night (dark) for them just as it was for everybody else.

In the terrible desert, which normally is the domain of impurity, a region in which the forces of the kelipa are at home (Zohar I, page 126) the Israelites were the beneficiaries of the heavenly light within the boundaries of their camp; outside their camp it was night (dark) for them just as it was for everybody else.

Normally, the Israelites did not travel at night. Whenever G‑d wanted them to travel at night, however, they did not require the light dispensed by the pillar of fire within their camp, as G‑d’s light illuminated every place within their camp. The pillar of fire was needed only to illuminate the way beyond the boundaries of their camp.

This is what the Torah had in mind when it wrote "to provide light for them". The reason G‑d had to provide this additional light was "so that they could travel by this light both by day and by night." Just as the Israelites were able to see into the distance by day without recourse to the pillar of fire, so at night, the pillar of fire provided illumination for them equal to that of the sunlight by day.

This then explains the wording of the Torah: "to enable you to see by it," (Deut. 1:33) But this is not in agreement with Rashi’s explanation.

[Selected with permission from the five-volume English edition of "Ohr HaChaim: the Torah Commentary of Rabbi Chaim Ben Attar" by Eliyahu Munk.]