Let us start with a simplified bullet point list of major world religions:
- Judaism - we are God's chosen people and we communicate and negotiate our existence with God
- Judeo-Christianity - we are promoted from chosen people to children of God
- Islam - we are God's slaves or at best tenants and have to submit to the Supreme being
- Buddhism - God is the void and we are happy to join the void
- Hinduism - God is the system of the world
The story goes like this - in comic-book grand narrative style:
Abraham sees a burning bush and realizes that the void in his soul is the only void. The void is unique. The sole and universal God speaks to him. From this event Judaism has developed as a practice of the chosen people to enter into dialogue with the Absolute.
Jesus comes along as an activist for existence and claims that he is the Christ, totally human and totally divine - and designated to die and be resurrected to prove all that. So starts the development of Christianity and it starts with Christ as the first existentialist activist. He claims that by accepting death we become children and heirs of God and God has become one of us. He is not a teacher, not a sage - but an activist like we have them nowadays. The actions of Jesus as Christ, the death and resurrection are presaging the "postmodernism" of Nietzsche and company.
Judeo-Christianity splits off the Orthodox East and the ancient original rites and develops into Catholicism and Protestantism in the West. They all become institutions. Judeo-Christians think themselves to be children of God and so having to behave like them.
Islam enters the stage - prior to Protestantism of course - and, while acknowledging the Abrahamic priority, reveals a teaching harsher than the Abrahamic one. Namely, we are not God's heirs and children - we are his slaves, or tenants at best, - and ought to live in submission. God is no longer the void but the whole of being and we are merely supplicants rather than participants.
Islam and Judeo-Christianity resemble each other in the judgment of human obligation as subordinates to God but differ very much in the concept of the status of human beings with respect to God.
The Asian developments of Hinduism and Buddhism, having taken place before Christ, resemble the split between Catholicism and Protestantism in Christendom. Hinduism is a religion of a God that is the system of the world. As far as I understand, human beings are not really important to this type of God. Perhaps for this reason, Buddhism basically asserts that human existence would be best served by its own denial and devolution into the divine void.
In my view Christ (born: Jesus) is still the guiding figure in the development of our modern religious sensibility.
The religion of Christ, if it existed, and which is not to be confused with the current forms of Christianity, would be profoundly humanistic. Christ does not care if God's existence can be proven - we, humans, have trouble proving our own existence to ourselves. That proof is otherwise known as Love - the elusive state of the soul that everybody is seeking. The main ethic of Christ's religion is not faith but a deep respect and awe for the courage of human existence. Or, to paraphrase Tillich, it is the faith that arises after God has died.
Here is a story by a Polish writer, Witold Gombrowicz, told in his autobiographical novel - "Trans-Atlantic." He gets stranded in Buenos Aires in 1939 and cannot go back to Poland because the Germans started WWII. He stays in BsAs (he really lived there for 20 years or so) and observes his kin folk, arrived on the ship with him, immersed in the life of the locals. One of those people is an older Polish military officer who has a young adult son. The officer upholds high Polish moral standards for himself and his son and really wishes they could fight somehow against the enemy. Unbelievably, with his acquiescence, his son succumbs to the seduction of a rich, vaguely homosexual, Argentinian. The novel ends in a surreal party or orgy where the protagonists proclaim that the idea of sonship should take precedence over that of fatherhood. Or in splendid and clever French translation - "filistrie" over "patrie". The moral is that we will no longer serve the fatherland but forge ahead creating a "sonland." Or Christ taking over from the Father.
The religion of Christ really does not exist. What we have is a seed of the idea embedded in Judeo-Christianity as a sort of contraband. Not sure what to do with it presently, I suspect that in the right moment it will supply strength and a source of meaning to Western civilization.
Gombro's "Trans-Atlantic" shows that the religion of Christ can open its seed in our time, even when vaguely clamoring for various sorts of liberation, through such a thing as an LGBTQ moment.
Modern atheism is not helping because it covers up the existential void with a scientific void. Neither is the exhortation to return to Enlightenment values because they exclude anything beyond the rational and objective. Existentialism, psychoanalysis (Jung invoked Christ's model directly) and other modern and postmodern directions are aiming better. Somehow paradoxically, they stand with Christ taking the position of profound respect for the courage of existence which will allow us, in due time, surpass Judeo-Christianity as well as Enlightenment.