The word [referring to "pillar"] comes from the word to stand, referring to pure staticism, reliability. The images of cloud and fire, on the other hand, are both volatile forces. They are the antithesis of reliability and predictability. In the experience of the wilderness at this stage in the history of Israel the dynamic is in the ascendant vis-à-vis the static. Once the Israelites are settled in the Land, and the holy Temple built, then it may be said that the static supervenes the dynamic. The tabernacle, which Moses has erected at the conclusion of the Book of Exodus, is a middle position parallel to the middle position which the covenant at Sinai represents between the original covenant of Abraham which was all vision, fire and faith and the later covenant on the plains of Moab which was all facts and practical reality.