The doctrine of the Unity of God is held in contradistinction
to _Polytheism_, which is belief in a multiplicity of gods;
_Tri-theism_, which teaches that there are three Gods--that
is, that the Father, the Son, and the Holy Ghost are, specifically,
three distinct Gods; and to _Dualism_, which teaches that
there are two independent divine beings or eternal principles, the
one good, and the other evil, as set forth especially in Gnostic
systems, such as Parseeism.

a) The Scriptures Assert the Unity of God.

Deut. 6:4--"Hear, O Israel; the Lord our God is one Lord"; or, "The
Lord our God, the Lord is one." Isa. 44:6-8--"First.... last....
beside me there is no God." Isa. 45:5--"There is none else,
there is no God beside me." 1 Tim. 2:5 "There is one God." 1 Cor.
8:4--"There is none other God but one."

That God is one, that there is no other, that He has no equal is
the forceful testimony of above fifty passages in the Scriptures.
The fundamental duty of life, namely, the devotion of the entire
being to the Lord, is based upon the Unity of God: "The Lord....is
one .... therefore thou shalt love the Lord thy God with _all_
thy heart," etc.

No other truth of the Scripture, particularly of the Old Testament,
receives more prominence than that of the Unity of God. This
truth is clearly pronounced also in the material universe; it is
the introduction and conclusion of all scientific researches. Any
other representation contradicts both creation and revelation. Its
denial is a proper object for the ridicule of every thinking man,