Are there more Gods than one?
There is but one only, the living and true God.1
Scripture proofs
The Westminster Assembly's proof texts (KJV). The bracketed numbers in the answer above mark the clause each set of references supports; expand a row to read the verses.
1 Deut. 6:4; 1 Cor. 8:4, 6; Jer. 10:10
Hear, O Israel: The LORD our God is one LORD:
1 Cor. 8:4 As concerning therefore the eating of those things that are offered in sacrifice unto idols, we know that an idol is nothing in the world, and that there is none other God but one.
1 Cor. 8:6 But to us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ, by whom are all things, and we by him.
But the LORD is the true God, he is the living God, and an everlasting king: at his wrath the earth shall tremble, and the nations shall not be able to abide his indignation.
This doctrine across the Standards
Where the Confession and the Westminster Shorter Catechism treat the same matter, so the question can be studied alongside its parallel statements.
In the Westminster Confession
II.1 There is but one only living and true God, who is infinite in being and perfection, a most …
There is but one only living and true God, who is infinite in being and perfection, a most pure spirit, invisible, without body, parts, or passions, immutable, immense, eternal, incomprehensible, almighty, most wise, most holy, most free, most absolute, working all things according to the counsel of his own immutable and most righteous will, for his own glory; most loving, gracious, merciful, long-suffering, abundant in goodness and truth, forgiving iniquity, transgression, and sin; the rewarder of them that diligently seek him; and withal most just and terrible in his judgments; hating all sin, and who will by no means clear the guilty.
→ II.1 · Of God, and of the Holy TrinityII.2 God hath all life, glory, goodness, blessedness, in and of himself; and is alone in and unto himself …
God hath all life, glory, goodness, blessedness, in and of himself; and is alone in and unto himself all-sufficient, not standing in need of any creatures which he hath made, nor deriving any glory from them, but only manifesting his own glory in, by, unto, and upon them: he is the alone fountain of all being, of whom, through whom, and to whom are all things; and hath most sovereign dominion over them, to do by them, for them, or upon them whatsoever himself pleaseth. In his sight all things are open and manifest; his knowledge is infinite, infallible, and independent upon the creature; so as nothing is to him contingent or uncertain. He is most holy in all his counsels, in all his works, and in all his commands. To him is due from angels and men, and every other creature, whatsoever worship, service, or obedience, he is pleased to require of them.
→ II.2 · Of God, and of the Holy TrinityII.3 In the unity of the Godhead there be three persons, of one substance, power, and eternity: God the …
In the unity of the Godhead there be three persons, of one substance, power, and eternity: God the Father, God the Son, and God the Holy Ghost. The Father is of none, neither begotten nor proceeding; the Son is eternally begotten of the Father; the Holy Ghost eternally proceeding from the Father and the Son.
→ II.3 · Of God, and of the Holy TrinityVIII.2 The Son of God, the second person in the Trinity, being very and eternal God, of one substance, …
The Son of God, the second person in the Trinity, being very and eternal God, of one substance, and equal with the Father, did, when the fulness of time was come, take upon him man's nature, with all the essential properties and common infirmities thereof, yet without sin: being conceived by the power of the Holy Ghost in the womb of the Virgin Mary, of her substance. So that two whole, perfect, and distinct natures, the Godhead and the manhood, were inseparably joined together in one person, without conversion, composition, or confusion. Which person is very God and very man, yet one Christ, the only mediator between God and man.
→ VIII.2 · Of Christ the MediatorIn the Westminster Shorter Catechism
Q.4 What is God?
God is a Spirit, infinite, eternal, and unchangeable in his being, wisdom, power, holiness, justice, goodness, and truth.
→ Open Q.4Q.5 Are there more Gods than one?
There is but one only, the living and true God.
→ Open Q.5Q.6 How many persons are there in the Godhead?
There are three persons in the Godhead; the Father, the Son, and the Holy Ghost; and these three are one God, the same in substance, equal in power and glory.
→ Open Q.6