Hubbles says

Hubbles observations suggested that there was a time,called the Big bang,when the universe was infinitesmallysmall and infinitely dense.Under such conditions all the laws of science,and therefore all ability to predict the future,would break down.One may say that time had a begining at the big bang,in the sensee that earlier times simply would not be defined .It should be emphasised that this begining in time is very different from those that had been considered previously.In an unchanging universe a begining in time is something thas to be imposed by some being outside the universe;there is no physical necesity for the begining.One can imaginethat God created the universe at literally any time in the past.On the other hand , if the universe is expanding there may be physical reasons why there had to be begining.One could still imagine that God created the universe at the instant of the Big Bang,or even afterwards in just such a way as to make it look as through there had been Big Bang,it would be meaningless to suppose that it was created before the Big bang.