Ultimately, we don't know where the energy of the big bang came from or if it even had to come from anywhere. But - it wasn't an explosion, it was more like akin to a vessel of hot water expanding and cooling, and in the course of that, the water condenses and complexice crystals and snow flakes form. The cooling atoms fused together to form more and more complex matter.
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition
