There are not a few ambiguous Biblical passages that teach that there is only one God, but many explicit passages that clearly declare this cardinal truth. Each of the following 28 passages explicitly teach that there is one — and only one — true and living God. The Mormon plurality of Gods doctrine (found most explicitly in the Pearl of Great Price/Book of Abraham 4-5) contradicts this fundamental biblical teaching.
Did you know that the translators of the King James Bible designed a simple code system into their translation to designate the various Hebrew names for God in the Old Testament? Understanding this system unlocks profound new insights into the Scriptural teaching about the nature and character of God. "The Bible states emphatically and repeatedly that there is only one God, it declares that Elohim is Jehovah, and it uses the names Elohim, Jehovah, and Adonai interchangeably."
Joseph Smith apparently wanted to set his followers straight when he proclaimed the following at the Mormon Church's General Conference in April, 1844: I am going to tell you how God came to be God. We have imagined and supposed that God was God from all eternity. I will refute that idea, and take away the veil, so that you may see. … It is the first principle of the Gospel to know for a certainty the character of God and to know...that he was once a man like us.... (“King Follett Discourse,” Journal of Discourses 6:3-4, also in Teachings of the Prophet Joseph Smith, 345-346, and History of the Church, vol. 6, 305-307, emphasis added)