21, 22. the Lord went before them—by a visible token of His presence, the Shekinah, in a majestic cloud (Ps 78:14; Ne 9:12; 1Co 10:1), called "the angel of God" (Ex 14:19; 23:20-23; Ps 99:6, 7; Isa 63:8, 9).

     39. covering—in sense of protection (compare Ex 13:21; Nu 10:34). In the burning sands of the desert the cloud protected the congregation from the heat of the sun; an emblem of God's protecting favor of His people, as interpreted by Isaiah (Isa 4:5, 6; compare Nu 9:16).