Charles Ellicott Commentary Exodus 40:36-38

"And when the cloud was taken up from over the tabernacle, the children of Israel went onward, throughout all their journeys: but if the cloud was not taken up, then they journeyed not till the day that it was taken up. For the cloud of Jehovah was upon the tabernacle by day, and there was fire therein by night, in the sight of all the house of Israel, throughout all their journeys." — Exodus 40:36-38 (ASV)

The cloud was from then on, in a distinctive way, attached to the Tabernacle. As a cloud it rested upon it by day; as a pillar of fire by night. Only in one case was it removed, namely, when it was the Divine will that Israel should march. (See Numbers 9:15-22.)