For me, the Old Testament is a narrative describing and chronicling “the numinous awe” of the Hebrew people (see Otto’s Idea of the Holy). Sometimes their perception of it was primitive, sometimes misdirected. But Abraham and Moses and Isaiah and some of the other prophets grasped it as best they could from where they were. The “numinous awe” that has always been present in every human heart emerged for these faithful people as a “person” and a “revelation” speaking from somewhere outside of this world.
As CS Lewis wrote: “Either it [numinous awe] is a mere twist in the human mind, corresponding to nothing objective and serving no biological function, yet showing no tendency to disappear from that mind at is fullest development in poet, philosopher, or saint: or else it is a direct experience of the really supernatural, to which the name Revelation might properly be given” (Problem of Pain 10).