Exodus 40:36-38

Now whenever the cloud was taken up from over the Tabernacle, Bnei-Yisrael went onward, throughout all their journeys. But if the cloud was not taken up, then they did not move out until the day that it was. For the cloud of ADONAI was on the Tabernacle by day and a fire was there by night, in the sight of all the house of Israel throughout all their journeys.