Exodus 40:36-38

In all their journeys, whenever the cloud was taken up from over the tabernacle, the Israelites would set out; but if the cloud was not taken up, then they did not journey on until the day when it was taken up. For throughout all their journeys, the cloud of the LORD was on the tabernacle by day, and there was fire in it by night, in the sight of all the house of Israel.