Why does the Holy Bible emphasize the oneness of God and that there is no other God beside Him (2 Sam. 7:22)?

If there were more than one God, it would be possible to compare among them; God would not have been absolute in His perfection. Also, if there were more than one God, God would not be ineffable, nor would it be impossible to describe His essence.

St. Clement of Alexandria insists, “God is one, and He is more than one, beyond unity.”³⁵² And St. Athanasius of Alexandria finds the unity of God reflected in the order and harmony of the world. If there were many gods, the world would not be harmonious.

Some philosophers thought that there are many gods, they believed that these gods wage war upon each other, and they ascribed a vain glory to these false gods; none of which is worthy of the One God who is absolute in His perfection.