Musnad Abu Ya'la al-Mawsili 147:41

Mujahid ibn Musa al-Khutali narrated to us, Abu Wahb al-Sahmi narrated to us, Sulayman al-Hadrami narrated to us, from Anas ibn Malik, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "If Allah intends good for a people, He tries them."