Universe Expansion

I have been watching videos over youtube about the scientific fact that the Universe is being expanding through the very start of its life,'THE BIG BANG'. The endless Universe created out of nothing can actually be inflated to such a boundless space and acumulate an amount of mass no one can ever imagine to come into being out of nothingness, is the biggest reality of our universe. I have been thinking what would be the reason for the creation of this huge,if GOD really exist, or the cause of it,if it came into being spontaneously.
          Being a Muslim, I relize that human beings are the only intelligent life form in the Universe so we are the reasons of it.But what difference can we make with ourselves to this endless and soo huge place? Just imagine yourself standing on the porch of your house,where your house is big enough to be recognised in a full view of your city blog,and the city blog in a full view of the city,and the city in the state,state on the world map,our planet Earth having considerable size among the other Planets of the Solar system,Solar system in turn to the Milky way(our Galaxy) which in turn contains billions of stars(of which our Sun is the one),and then trying to find out your home among the 1,25,000 Galxies in the whole Universe...........! Its just a thing you can only imagine,but at this place I have to mention another marvelous fact that we humans being soo minute to this universe are still able to take a full picture of the whole place in our imagination.So it means human's imagination is still bigger than the Universe itself. With this I came to realize that, this one reason, and many more we can have, is the reason we are here.Regardless the size and the influence we can have we still have much grater impact.