Deuteronomy 5:7
You shall have no other gods before Me.

Isaiah 45:5-6
I am the LORD, and there is no other; there is no God but Me. I will equip you for battle, though you have not known Me, / so that all may know, from where the sun rises to where it sets, that there is none but Me; I am the LORD, and there is no other.

Matthew 4:10
“Away from Me, Satan!” Jesus told him. “For it is written: ‘Worship the Lord your God and serve Him only.’”

1 Corinthians 8:4-6
So about eating food sacrificed to idols: We know that an idol is nothing at all in the world, and that there is no God but one. / For even if there are so-called gods, whether in heaven or on earth (as there are many so-called gods and lords), / yet for us there is but one God, the Father, from whom all things came and for whom we exist. And there is but one Lord, Jesus Christ, through whom all things came and through whom we exist.

Deuteronomy 6:14
Do not follow other gods, the gods of the peoples around you.

Isaiah 44:6-8
Thus says the LORD, the King and Redeemer of Israel, the LORD of Hosts: “I am the first and I am the last, and there is no God but Me. / Who then is like Me? Let him say so! Let him declare his case before Me, since I established an ancient people. Let him foretell the things to come, and what is to take place. / Do not tremble or fear. Have I not told you and declared it long ago? You are My witnesses! Is there any God but Me? There is no other Rock; I know not one.”

1 John 5:21
Little children, keep yourselves from idols.

2 Kings 17:35
For the LORD had made a covenant with the Israelites and commanded them, “Do not worship other gods or bow down to them; do not serve them or sacrifice to them.

Jeremiah 25:6
Do not follow other gods to serve and worship them, and do not provoke Me to anger with the works of your hands. Then I will do you no harm.’

1 Timothy 2:5
For there is one God, and there is one mediator between God and men, the man Christ Jesus,

Hosea 13:4
Yet I am the LORD your God ever since the land of Egypt; you know no God but Me, for there is no Savior besides Me.

Acts 17:22-31
Then Paul stood up in the meeting of the Areopagus and said, “Men of Athens, I see that in every way you are very religious. / For as I walked around and examined your objects of worship, I even found an altar with this inscription: TO AN UNKNOWN GOD. Therefore what you worship as something unknown, I now proclaim to you. / The God who made the world and everything in it is the Lord of heaven and earth and does not live in temples made by human hands. ...

Psalm 81:9
There must be no strange god among you, nor shall you bow to a foreign god.

1 Kings 18:21
Then Elijah approached all the people and said, “How long will you waver between two opinions? If the LORD is God, follow Him. But if Baal is God, follow him.” But the people did not answer a word.

Romans 1:21-23
For although they knew God, they neither glorified Him as God nor gave thanks to Him, but they became futile in their thinking and darkened in their foolish hearts. / Although they claimed to be wise, they became fools, / and exchanged the glory of the immortal God for images of mortal man and birds and animals and reptiles.