WayneLigon
Adventurer
What I find interesting about early Judaism is there does seem to at least be this sense that other gods exist (you just are not supposed to worship them) but then it increasingly becomes more monotheistic than henotheistic.
It is really, really murky - very likely having been deliberately obscured by successive rounds of purges, etc, etc.
There is definitely a period where the Jews are 'there are other gods, but El/Yah/whatever wants us to hold Him Preeminent', then X happens and suddenly they are 'There are no other gods and never have been'.
Some scholars put X at around the time of the Exodus, some push it back onto Abraham. The most likely explanation is that there is a schism within the temple, with one faction finally getting tired of losing, falling on the other with swords, then as winners usually do, making up whatever they needed to justify and legitimize their victory. There's also the idea that it's a more gradual take-over of the religion by internal factions that develop - finally they just outlive everyone else, burn the scrolls that contradict them, and suddenly 'We're monotheists! And always have been!'.
Some other scholars point to 'culture building', as the elders cobble together laws and customs in order to differentiate their people from all the other tribes and set them apart as something special. They don't have to make sense, they just have to be different, so different and memorable that people go 'Oh, they do X? They must be the Y people!' (You see the most blatant example of this in Leviticus).