All events that take place in this world, even those apparently fortuitous or casual, are comprehended in the order of divine Providence, on which fate depends. This has been foolishly denied on the assumption that the divine mind is like ours, a mistaken assumption... The nature of the proximate causes settles whether an effect should be called necessary or contingent. Yet every effect depends on the divine will.. This cannot be said of the human will, or indeed of any created cause, for all causes, except God, are confined in a system of necessity and contingency, whether they be variable or constant in their activity. The divine will cannot fail, but we cannot therefore ascribe necessity to all its effects.
"Necessity" and "contingency" are terms also used to describe the evolutionary process. The book I found this quote in was actually discussing convergence and contingency in evolution, not theology or even religious history (the book in question is Crucible of Creation by Simon Conway Morris). Often Christians take issue with evolution because it is perceived as blind chance, when the same sort of chance aspects of evolution are accepted in other areas of life. Most Christians believe in some form of free will but at the same time believe that God has individual plans for us all which takes place in a greater narrative which is planned out to an extent. Here we see principles of necessity effectively funnelling contingent aspects of life. It is no stretch to apply this to evolution and so this Aquinas quote is useful for anyone grappling with the concept of contingency in the history of life.