Musnad Ahmad 696:4

Bahz and Hajjaj narrated to us, they said: Sulayman ibn al-Mughirah narrated to us, from Thabit, from Abd al-Rahman ibn Abi Layla, from Suhayb, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "I am amazed by the affair of the believer. Indeed, the entire affair of the believer is good for him, and that is not for anyone except the believer. If good fortune befalls him, he gives thanks, and that is good for him. And if adversity befalls him, he is patient, and that is good for him."