St. Augustine: It is true that wicked men do many things contrary to God's will...

It is true that wicked men do many things contrary to God's will; but so great is His wisdom and power, that all things which seem adverse to His purpose do still tend towards those just and good ends and issues which He Himself has foreknown. 

And consequently, when God is said to change His will, as when, e.g., He becomes angry with those to whom He was gentle, it is rather they than He who are changed, and they find Him changed in so far as their experience of suffering at His hand is new, as the sun is changed to injured eyes, and becomes as it were fierce from being mild, and hurtful from being delightful, though in itself it remains the same as it was.

St. Augustine