“If you want to make an apple pie from scratch, you must first create the universe.” – Carl Sagan
That includes the law of gravity. Creation ex nihilo means “from nothing” not “from the law of gravity”. In fact, what Hawking has stumbled over, without realizing it, is the doctrine of the Trinity and, in particular, the reality of the Logos. Unfortunately as a technician and a member of the UK Chattering Class who no longer get adequate philosophical or theological training (such things are beneath contempt), his training has left him wholly unprepared to see what he is looking at.
Little round planet
In a big universe
Sometimes it looks blessed
Sometimes it looks cursed
Depends on what you look at obviously
But even more it depends on the way that you see – Bruce Cockburn