exodus 40:36 And when the cloud was taken up from over the tabernacle, the children of Israel went onward in all their journeys: - Free Bible Online

      36. when the cloud was taken up from over the tabernacle--In journeying through the sandy, trackless deserts of the East, the use of torches, exhibiting a cloud of smoke by day and of fire by night, has been resorted to from time immemorial. The armies of Darius and Alexander were conducted on their marches in this manner [FABER]. The Arab caravans in the present day observe the same custom; and materials for these torches are stored up among other necessary preparations for a journey. Live fuel, hoisted in chafing dishes at the end of long poles, and being seen at a great distance, serves, by the smoke in the daytime and the light at night, as a better signal for march than the sound of a trumpet, which is not heard at the extremities of a large camp [LABORDE]. This usage, and the miracle related by Moses, mutually illustrate each other. The usage leads us to think that the miracle was necessary, and worthy of God to perform; and, on the other hand, the miracle of the cloudy pillar, affording double benefit of shade by day and light at night, implies not only that the usage was not unknown to the Hebrews, but supplied all the wants which they felt in common with other travellers through those dreary regions [FABER, HESS, GRANDPIERRE]. But its peculiar appearance, unvarying character, and regular movements, distinguished it from all the common atmospheric phenomena. It was an invaluable boon to the Israelites, and being recognized by all classes among that people as the symbol of the Divine Presence, it guided their journeys and regulated their encampments (compare Ps 29:1-11; 105:1-45).

JFB.