There is an interesting concept presented by someone i can't, for the life of me, remember who it was, that maintained that the abstract thought was far less able in grasping complex concepts in the past, as it was the development of language that elevated it to allow us humans to grasp those. that "theory" maintains that a visual thinking, or imagining certain things, is older than the abstract thought and that, for example, the first human being that ever felt remorse for killing a dog, because it was cute, didn't just abstractly thought or discovered he had conscience but actually visualized a being (angel/demon/etc..) that told him not to kill cute dogs (Prior to that phase, not hunting a beast for meat was perceived as bizarre). the inner voice only later introduced when people started exchange that experience and ideas and the exterior visual image became an inner visual image (Humans began to understand the visual entity is not out there) and only then an inner voice.
That theory also suggests that a lot of concepts of god/gods is actually only the birth of abstract concepts that started to take shape as visual entities that explained stuff and that the evolution of religions/gods is simply an evolution of human understanding of universal laws, either physical or moral laws.
The change in god throughout the revelations is actually the different and evolving ability of the "prophets" to perceive, understand and communicate their insights.
Regardless if humans actually visualized stuff externally, because their language was severely limited, they communicated the theories/concepts through metaphors so they could explain them to themselves and to others. in essence, if abraham had lived today, he wouldn't have "seen" nor communicated an angel diverting his hand from killing his son, nor a single powerful god. he would have thought that sacrifice is immoral and that there is a unified set of rules that apply to all and communicated so. its not that he merely couldn't communicate it, its that he couldn't actually understand it without visualizing a giant, extremely powerful being.