P.E.A.C.E and Blessings...
He is the ultimate good, beyond our comprehension. I personally think He exists because I have experienced Him.

Hmmm....some how eye don't think thats going to be enough to convince Jersey. lol.
(NO OFFENCE INTENDED TO U, SCRATCHINGMYHEAD)
P.E.A.C.E Jersey...
What is a God, exactly, and why do you think one exists?
The first question, "what is a God exactly?" is something that seems to be different for a lot of people, depending on religion, experience, the characteristics they apply to "God", to the point where it seems easiest if eye give U a definition of God and Cee if it applies to me.
GOD - A being of supernatural powers or attributes, believed in and worshiped by a people, especially a male deity thought to control some part of nature or reality.
Eye'll use the above meaning as it seems to apply to the common conception of God.
Firstly eye don't believe in supernatural powers. Nothing in this Universe happens above or beyond the Laws that have been put in place.
Do eye worship a particular entity thought to control some part of nature or reality?
Yes. Infact eye worship (to render reverence and homage to) many entities that control a part of nature or reality. For example, eye worship the Sun, for it controls things like light, warmth, our concept of time (passing of years, days etc.). Does that make it a God, eye don't know, it seems to.
At the end of the day, though, all exists within The ALL (El Kuluwm), that is the God of Gods. It seems that this Universe functions by a Supreme Intelligence, that intelligence though is again, just another part of the ALL. Which is why the best title eye, myself can come up with would be The ALL. Anything else seems to define and limit what is limitless and undefinable.
SHEM HETEP
(DONT WORRY EYE KNOW THIS WILL PROBABLY NOT CONVINCE U EITHER).