Exodus 40:36-38

And when the cloud lifted itself up from over the tabernacle, the sons of Israel went onward in all their journeys; but if the cloud did not lift itself up, then they did not journey until the day that it lifted itself up. For the cloud of the LORD was upon the tabernacle by day, and the fire was in it by night, in the sight of all the house of Israel, throughout all their journeys.