The Trinity was a compromise. When Christianity was killing itself over whether Jesus was the same substance as God the father, a compromise was devised to keep people from killing each other. That is Jesus was God the father, but wasn't. It was never meant to be understood by anyone, just make everyone think their side one the debate. Sort of like college football. There is no metaphor to explain it. It is just one of the many stupid things that Christianity has adopted for which there is no real Biblical reference.
"On Earth as it is in Heaven, the Cosmic Roots of the Bible" available on the Amazon.
