Who created the universe and why?

According to Rigved (MAND 10,sUKTA 129, Mantra 3)In the beginning the whole was enveloped in utter darkness.Nothing was discernible.It was a dark night.Matter was in its very elementary form.It was like either.The whole universe,completely overspread by darkness,was insgnificantly small compared with the infinite God who thereafter,by His Omnipotience,evolvedthis cosmic world.