The Cloud of the Lord

In all the travels of the Israelites,
whenever the cloud lifted from above the tabernacle,
they would set out;
but if the cloud did not lift,
they did not set out --
until the day it lifted.
So the cloud of the Lord was over the tabernacle by day,
and fire was in the cloud by night,
in the sight of all the house of Israel
during all their travels.

(Exodus 40: 36-38)