God is everything the narcissist ever wants to be: omnipotent, omniscient, omnipresent, admired, much discussed, and awe inspiring. God is the narcissist's wet dream, his ultimate grandiose fantasy. But God comes handy in other ways as well.
The narcissist alternately idealizes and devalues figures of authority.
In the idealization phase, he strives to emulate them, he admires them, imitate them (often ludicrously), and defends them. They cannot go wrong, or be wrong. The narcissist regards them as bigger than life, infallible, perfect, whole, and brilliant. But as the narcissist's unrealistic and inflated expectations are inevitably frustrated, he begins to devalue his former idols.
Now they are "human" (to the narcissist, a derogatory term). They are small, fragile, error-prone, pusillanimous, mean, dumb, and mediocre. The narcissist goes through the same cycle in his relationship with God, the quintessential authority figure.
But often, even when disillusionment and iconoclastic despair have set in - the narcissist continues to pretend to love God and follow Him. The narcissist maintains this deception because his continued proximity to God confers on him authority. Priests, leaders of the congregation, preachers, evangelists, cultists, politicians, intellectuals - all derive authority from their allegedly privileged relationship with God.
Religious authority allows the narcissist to indulge his sadistic urges and to exercise his misogynism freely and openly. Such a narcissist is likely to taunt and torment his followers, hector and chastise them, humiliate and berate them, abuse them spiritually, or even sexually. The narcissist whose source of authority is religious is looking for obedient and unquestioning slaves upon whom to exercise his capricious and wicked mastery. The narcissist transforms even the most innocuous and pure religious sentiments into a cultish ritual and a virulent hierarchy. He prays on the gullible. His flock become his hostages.
Religious authority also secures the narcissist's narcissistic supply. His coreligionists, members of his congregation, his parish, his constituency, his audience - are transformed into loyal and stable sources of narcissistic supply. They obey his commands, heed his admonitions, follow his creed, admire his personality, applaud his personal traits, satisfy his needs (sometimes even his carnal desires), revere and idolize him.
Moreover, being a part of a "bigger thing" is very gratifying narcissistically. Being a particle of God, being immersed in His grandeur, experiencing His power and blessings first hand, communing with him - are all sources of unending narcissistic supply. The narcissist becomes God by observing His commandments, following His instructions, loving Him, obeying Him, succumbing to Him, merging with Him, communicating with Him - or even by defying him (the bigger the narcissist's enemy - the more grandiosely important the narcissist feels).
Like everything else in the narcissist's life, he mutates God into a kind of Inverted Narcissist. God becomes his dominant source of supply. He forms a personal relationship with this overwhelming and overpowering entity - in order to overwhelm and overpower others. He becomes God vicariously, by the proxy of his relationship with Him. He idealizes God, then devalues Him, then abuses him. This is the classic narcissistic pattern and even God himself cannot escape it.
Based on my book "Malignant Self Love - Narcissism Revisited"