God's glory
Several instances throughout Exodus (e.g., Ex 16:10; 34:5) have made clear that the visible manifestation of Yahweh’s presence often occurs as a cloud. Since the Israelites conceived of Yahweh as invisible, they needed a visible entity—a reminder or symbol that could be seen by the human eye—to reassure them that Yahweh was indeed present with them. That visible entity is often referred to in the OT as the “glory” (kabod) of Yahweh. Isa 40:5, e.g., states that it is the “glory of the LORD” that “all people will see.” Once the construction and arrangement of the tabernacle in Exodus are complete, the glory of Yahweh, in the form of a cloud, fills the place that Moses cannot even enter it (Ex 40:35). It seems, therefore, to have been more than something that could merely be seen; it could be sensed in other ways. At one point in Exodus, the “glory” is called a “consuming fire” (24:17). The glory of Yahweh was reassuring and fear-inspiring all at the same time. This is reminiscent of