I said : Messenger of Allah (May peace be upon him) what happens to the offspring of believers ? He replied : They are joined to their parents. I asked : Messenger of Allah! Although they have done nothing ? He replied : Allah knows best what they were doing. I asked : what happens to the offspring of polytheists, Messenger of Allah ? he replied! They are joined to their parents. I asked : Although they have done nothing? He replied : Allah knows best what they were doing.
Sunan Abi Dawud Book 42, Hadith 117