Believer asks: Perhaps the Big Bang created the universe, but Who caused the Big Bang?
Skeptic replies: Science is still working on the question of what caused the Big Bang to bang. Meanwhile asking “who caused it” is a God of the gaps question. That is, religious people may say “God did it” until science discovers the answer.
For example, Isaac Newton (1643-1728) developed a mathematical equation for the motion of the planets in orbits thanks to the force of gravity. His equation explained why planets and comets orbited the sun.
At the same time, Newton couldn't account for the so-called plane of the planets, in which their orbits lay on practically the same plane or level around the sun and not perpendicular to each other. In the end
Decades later the astronomer Pierre-Simon LaPlace gave an explanation for the plane of the planets according to a natural law. So it was bye-bye to the God of the gaps argument.
The point is that one day physicists might discover the natural force that caused the Big Bang. Until that happens the “God of the gaps argument” people need to have patience.