Then a cloud covered the tent of the congregation, and the glory of the LORD filled the tabernacle.  And Moses was not able to enter into the tent of the congregation, because the cloud abode thereon, and the glory of the LORD filled the tabernacle.
And when the cloud was taken up from over the tabernacle, the children of Israel went onward in all their journeys: but if the cloud were not taken up, then they journeyed not till the day that it was taken up.  For the cloud of the LORD was upon the tabernacle by day, and fire was on it by night, in the sight of all the house of Israel, throughout all their journeys.                   Exodus 40:34-38

References: Exodus 40:1-33; Numbers 9:15-23; Isaiah 4:5-6; 6:1-7; Revelation 15:8; 21:3, 23-24