Lawrence Boadt has this interesting comment on the book of Numbers: Like the laws of Leviticus, the materials gathered in Numbers come from many different ages. The oracles of Balaam with their archaic poetic lines and frozen expressions originated in the time of the judges, and the poems in Numbers 21:17-18, the “Song of the Well,” and in Numbers 21:27-30, the “Lament over Heshbon,” may also be quite ancient fragments. These, together with the story narrative, are from the J [Jahwist] and E [Elohist] sources, while most of the laws are later and belong to the P [Priestly] source. P also tied the events in Numbers to the Book of Exodus by listing all of the desert stopping places of Israel in chapter 33. Altogether, there are twelve major stages in their journey up to the arrival at the promised land. Six of these lead up to Mount Sinai, and six lead away from it. P took the first six from Exodus 12-19, and the last six from Numbers 20-22, creating a single narra...