Maliks Muwatta Book 050, Hadith Number 007.

Section : The Reward of the Invalid.

Yahya related to me from Malik that Muhammad ibn Abdullah ibn Abi Sasaca said that he heard Abu'l-Hubab Said ibn Yasar say that he had heard Abu Hurayra say, "The Messenger of Allah, may Allah bless him and grant him peace, said, 'Allah afflicts the one for whom He desires good.'"