Qur'an, An-Nisa, Surah 4:78b-79b
When people are blessed with good fortune, they say, "This is from God." And when misfortune comes, they say, "This is Muhammad's fault." Let them understand that all is from God. What has happened to people that they show such lack of understanding? Whatever good befalls you, it is from God; and whatever evil befalls you, it is your own fault.