Since there is no demonstrable evidence that God exists, where does the concept of "God" come from? Obviously, from the minds of humans. We create the idea of God, which includes the fantasy that God created us.
The November 9, 2020 issue of The New Yorker has an interesting review of a book by a Stanford anthropologist, T.M. Luhrmann, "How God Becomes Real."
Basically, by people doing things that conjure up their imagined God, in somewhat the same way as the reader of a novel throws themself into the story line to such a degree, the fictional creation can seem real while the novel is being read.
This is the description of Luhrmann's book on Amazon.
How do gods and spirits come to feel vividly real to people―as if they were standing right next to them? Humans tend to see supernatural agents everywhere, as the cognitive science of religion has shown. But it isn’t easy to maintain a sense that there are invisible spirits who care about you. In How God Becomes Real, acclaimed anthropologist and scholar of religion T. M. Luhrmann argues that people must work incredibly hard to make gods real and that this effort―by changing the people who do it and giving them the benefits they seek from invisible others―helps to explain the enduring power of faith.
Drawing on ethnographic studies of evangelical Christians, pagans, magicians, Zoroastrians, Black Catholics, Santeria initiates, and newly orthodox Jews, Luhrmann notes that none of these people behave as if gods and spirits are simply there. Rather, these worshippers make strenuous efforts to create a world in which invisible others matter and can become intensely present and real. The faithful accomplish this through detailed stories, absorption, the cultivation of inner senses, belief in a porous mind, strong sensory experiences, prayer, and other practices. Along the way, Luhrmann shows why faith is harder than belief, why prayer is a metacognitive activity like therapy, why becoming religious is like getting engrossed in a book, and much more.
A fascinating account of why religious practices are more powerful than religious beliefs, How God Becomes Real suggests that faith is resilient not because it provides intuitions about gods and spirits―but because it changes the faithful in profound ways.
Here's an excerpt from the review by James Wood.
Modern Christians in the West like to think of themselves as believers who have left behind any cultic relationship with a usable God. Doubtless not a few of them harbor a special disdain for American Evangelicalism, with its gaudy, prosperous instrumentalism.
Certainly, if belief were plotted along a spectrum, at one end might lie the austere indescribability of the Jewish or Islamic God ("Silence is prayer to thee," Maimonides wrote) and at the other the noisy, all-too-knowable God of charismatic worship, happy to be chatted to and apparently happy to chat back.
But it is still a spectrum, and, indeed, any kind of petitionary prayer presumes a God onto whom one is projecting local human attributes. In this sense, you could say that Christianity is essentially a form of idolatry.
The difficult, unspeakable Jewish God becomes the incarnated Jesus, a God made flesh, who lived among us, who resembles us. Theodor Adorna and Max Horkheimer blamed Christian anti-Semitism on just this idolatry of the man-God: "Christ the incarnated spirit is the deified sorcerer." The called this "the spiritualization of magic."
Evangelicals are hardly the only Christian believers to draw this Jesus, the deified sorcerer, to them. I'm reminded of that whenever I see professional soccer players crossing themselves as they run onto the field, as if God really cared whether Arsenal beats Manchester United.
Luhrmann would say, with some justice, that in such cases we should focus more on the practice than on the beliefs. Crossing oneself is ritualistic, and she would probably add that the soccer player then performs on the field as if he and his team alone determined the outcome of the game, which is to say that -- in a sense -- he performs as if God didn't exist after all.
In "How God Becomes Real," Luhrmann calls this the art of possessing "flexible ontologies," because "people may talk as if the gods are straightforwardly real, but they don't act that way." A driver who prays that the car will stop without his using the brakes "would seem mad, not devout."
The real world, dependent on the laws of physics, runs easily alongside a highly elaborated and imagined belief-world, which shares several of he properties of fiction-making and fiction-reading. The Vineyard believers, Luhrmann discovers, learn how to "pretend that God is present and to make believe that he is talking back like the very best of buddies."
As with a fictional character, this God is at once absolutely real and not quite real. Luhrmann likens the capacity for imaginative absorption to being "engrossed in good magical fiction of the Harry Potter kind."
...Her [Luhrmann's] major refuge is a kind of therapeutic pragmatism. She's fond of the verb "work." Prayer works, belief works, real-making works, she says, in the sense that, as far as these believers are concerned, God is made real; and these prayer practices therapeutically change the people who practice them.
But does prayer "work" in the most important sense, of achieving what it proposes -- which is to communicate with an actually existing God? Luhrmann won't be drawn out, committed as she is to a kind of Feurbachian religious anthropology, in which God is merely the reality we conjure and create through our activities, imaginings, and yearnings.