"And the cloud of the L-rd was above them by day when they set forth from the encampment": Even over the lame and the blind and the zavim (those afflicted with a genital discharge) and the lepers.
Variantly: "And the cloud of the L-rd was above them by day": Whence is it derived that if one of the Jews withdrew from under the wings of the cloud, it withdrew with him until he returned? From "And the cloud of the L-rd was above them." Perhaps just as it protected them by day, so it protected them at night. (This is not so,) for it is written "by day" — It protected them by day and not at night. Granted, then, that the pillar of cloud did not protect them at night, but perhaps the pillar of fire provided light for them by day; it is, therefore, (to negate this) written (Shemot 40:38) "and fire was on it by night" — It gave light at night, but not in the daytime. Perhaps just as it gave light for Israel, so it gave light for the idolators. (This is not so,) for it is written (Shemot 40:38) "and fire was on it by night in the sight of all of the house of Israel" — It gave light for Israel, but not for the idolators. R. Shimon b. Elazar says: Whence is it derived that all the forty years that Israel were in the desert they did not require a lamp, but even if one entered a room within a room, a kind of torch entered with him until he returned? From (Shemot 40:38) "in the sight of all of the eyes of Israel in all of their travels" — Even if one entered a room within a room, the pillar of fire would give light before him.