The Lord went ahead of them as a pillar of cloud to show them the way during the day, and as a pillar of fire to provide them with light at night. Like this they could travel by day or night. Exo 14:19; Num 14:14; Deu 1:33; Deu 4:37; Psa 78:14; Psa 105:39; Neh 9:19