Although the Jewish omnipotent entity we refer to by tradition as God was first called "Yahweh" ("I am") by the Israelites, legend has it that the high priest of Israel passed from one to another his true name, made up of 72 Hebrew letters that, when spoken, would summon his presence before the speaker. This was required for their annual ritual of asking for forgiveness of the nation's sins - by asking face to face.
So what would happen if you found this combination? And what could you petition? Well, Jesus did provide a warning, "Fear not those who can destroy the body and then do no more... fear him who, after killing the body, can destroy the soul." (Luke 12:4-5)