I'm not asserting that God arose spontaneously. I'm asserting that God never arose. God simply is. He is the great "I AM" of the Bible. He is eternal. God is existence itself. All other things participate in existence, because existence is not an inherent part of their essence.
But God's essence and act of existence are the same. His essence is to be.
An infinite chain of causes cannot exist, because although the idea of an infinite series can exist, an actual infinite series cannot. Because for the series to become actual, it becomes finite.
I'm not asserting that the universe arose spontaneously. I'm asserting that the universe never arose. The universe simply is. It is the great "I AM" of the Bible. It is eternal. The universe is existence itself. All other things participate in existence, because existence is not an inherent part of their essence.
As I said, I find both paragraphs equally unsatisfying.