Monotheism is the belief that there is only one God in all places at all times. There were no gods of any kind that actually existed before God, and there will be no gods of any kind that actually exist after Him. We cannot become gods.  No one can become a god.

There are those that are called gods.

1 Cor. 8:5, “For even if there are so-called gods whether in heaven or on earth, as indeed there are many gods and many lords.”

But these so-called gods are not really gods by nature.

Galatians 4:8, “However at that time, when you did not know God, you were slaves to those which by nature are no gods.“

Sometimes people are referred to as gods, but that is only in reference to them being powerful and/or important.

• Psalm 82:6–7, “I said, ‘You are gods, and all of you are sons of the Most High.7 Nevertheless you will die like men and fall like any one of the princes.'”
• Exodus 4:16, “Moreover, he shall speak for you to the people; and he will be as a mouth for you and you will be as God to him.”
• Exodus 7:1, “Then the LORD said to Moses, ‘See, I make you as God to Pharaoh, and your brother Aaron shall be your prophet.'”

Monotheism is the teaching of the Bible (Isaiah 43:10, 44:6, 8, 45:5, 14, 18, 21, 22, 46:9, 47:8, John 17:3, 1 Cor. 8:5-6, Gal. 4:8-9).

• Isaiah 43:10, “‘You are My witnesses,’ declares the LORD, “And My servant whom I have chosen, So that you may know and believe Me And understand that I am He. Before Me there was no God formed, And there will be none after Me.”
• Isaiah 44:6, ” “Thus says the LORD, the King of Israel and his Redeemer, the LORD of hosts: ‘I am the first and I am the last, And there is no God besides Me.”
• Isaiah 44:8, “‘Do not tremble and do not be afraid; Have I not long since announced it to you and declared it? And you are My witnesses. Is there any God besides Me, Or is there any other Rock? I know of none.’ ””
• Isaiah 45:5, ” “I am the LORD, and there is no other; Besides Me there is no God. I will gird you, though you have not known Me;”