Reference: Cloud, Pillar Of
Cloud, Pillar of.
The pillar of cloud by day and of fire by night that God caused to pass before the camp of the children of Israel when in the wilderness. The cloud, which became a pillar when the host moved, seems to have rested at other times on the tabernacle, whence god is said to have "come down in the pillar."
It preceded the host, apparently resting on the ark which led the way.
etc.; Numb 9:15-23; 10:34