"As Christianity in its beginnings was surrounded by the polytheistic beliefs and practices of the pagan world, a clear and authoritative expression of Monotheism was necessary. Hence the symbols of faith, or creeds, open with the words: "I [we] believe in God"...(APOSTLES' CREED; ATHANASIAN CREED; NICENE CREED.)"
January 1, 1970
https://en.wikiquote.org/wiki/Monotheism