the actual world is not one among possible worlds, but is the only possible world, since God is bound to choose what is best.
 Bertrand Russell, A History of Western Philosophy (1945). copy citation

Context

“He was the last of the important Oxford scholastics. As a philosopher, he was not progressive; he was a realist, and a Platonist rather than an Aristotelian. He held that God’s decrees are not arbitrary, as some maintained; the actual world is not one among possible worlds, but is the only possible world, since God is bound to choose what is best. All this is not what makes him interesting, nor does it seem to have been what most interested him, for he retired from Oxford to the life of a country clergyman. During the last ten years of his life he was the parish priest of Lutterworth, by crown appointment.” source