In the world filled with so many believers of different gods, God has proved it time and time again that He is one and only true God and no one comes closer.
If you look at the Ten Commandments, you remember the story of Moses, the story of Exodus and Genesis where? It's there like the seed of Abraham in the start of the history of Israel where people joined Egypt for so many years.
They were forced under some certain kind of conditions to join in Egypt and labor as slaves. But the government of Egypt treated them like nothing and they worked under forced labor. So God proved with the kingdom of Egypt that He is the true God and there is nobody else.
So when He performed miracles and wonders, the God of Egypt cannot control it.
In Egypt they have so many things happening around and which they called out. When God came, He said, God turned water into wine and everything. When God turned the sea or the Givanna into blood, it caused the fish to die and this made everything and showed the proof that God really exists.
God displayed Himself as being God and powerful even in the Old Testament and New Testament. God has proven Himself time and time again that He exists. And through His creation, through His actions, through His nature, we cannot disprove that.