When Joseph Smith wrote the Book of Mormon around 1828 to 1829,
his theological background was in Protestant Christianity.
He believed what he was writing in the Book of Mormon narrative –
that God was Spirit.
At that time, everyone who followed Mormonism believed in the one God, who was a spirit. Many years later, Smith changed his theology and then altered the Book of Mormon passages to accommodate his changed thinking – separating God from Jesus. But he did not indicate that God had a body and he certainly did not change the verses in chapters 18 and 22 of the book of Alma, which specifically teaches that God is the “Great Spirit.”
Article Bible References
1 Timothy 1:17