This movie is wonderful. For me, it describes man's inability to own God. It's case for the non-existence of God is entirely placed within the realm of bitterness and judgement, as opposed to reason.
Someone who wishes to adopt this bitterness as a means for personal freedom from what they see as an improper creator can do so.. but that doesn't make it sensible.
I loved the parallel between the pastor/God relationship and the lover/pastor relationship. The shortcomings there are clearly drawn in a depiction of the human effort to please God. Naturally Bergman's bitter judgement depicts a pastor-God who is indifferent and/or spiteful towards a earnest and devoted creation. But in truth, the Biblical God is not so. The God that Ingmar grew up with (though through the strains of a legalistic and apparently extremely disciplinarian upbringing) is one who does fill all in all. As such, He gives a literal Spirit, much the same as the spirit of bitterness that rested on Ingmar, though opposite in that it experientially reconciles the human soul with God. Such a Spirit is given when one is genuinely teachable. But if bitterness is resident within a soul through a willfully distorted opinion towards personal or world events.. this Spirit remains aloof. Such things rest comfortably within the totalitarian knowledge and reasonably justified decisions of a truly monotheistic God.
The true God really doesn't owe us anything, but yet has given us everything. The lines of suffering in this earthly existence are not existent without the obvious self-righteousness and stubborn indignation of a humanity largely uninterested in being subject to a creator.. though still remaining irrevocably so.
The math of the universe is simply not indicative of the non-existence of God.. regardless of what a humanistic society might wish to teach it's children.