Exodus 40:34-38

Then the cloud covered the tent of meeting, and the glory of the LORD filled the tabernacle. Moses was not able to enter into the tent of meeting because the cloud settled on it, and the glory of the LORD filled the tabernacle. When the cloud was lifted up from over the tabernacle, the children of Israel would set out in all their journeys. But if the cloud was not lifted up, then they did not set out until the day that it was lifted. For the cloud of the LORD was on the tabernacle by day, and fire was on it by night, in the sight of all the house of Israel, throughout all their journeys.