God existing or 'existing' or just thinks he 'exists'?
The first thing god did after he created self, was to circumcise self. Yes, he has a penis; or else, Mary could have not been made impregnated, according to Luke and Matthew.
In order for god to be self sanctified, he had to shed some blood That's why the scribes say that only by shedding blood can god's people be sanctified or made holy.
But for some inexplainable and never to be known reason scribes say that god's blood just wasn't good enough to save the people---but only those that believed in god.
According to Matthew, Mary was impregnated by the holy spirit.
Circumcision was part of the covenant thing made with Abraham.
"The first covenant was between God and Abraham. ... You shall be circumcised in the flesh of your foreskins, and it shall be a sign of the covenant between me and you. Genesis 17. God promised to make Abraham the father of a great people and said that Abraham and his descendants must obey God"
This suggests (a la Freud) that the genesis of civilization was a traumatic (or primal) event, which is recognized in the continuance of the circumcision ritual.