Musnad Ahmad 652:70

Yunus and Surayj narrated to us, they said: Hammad narrated to us, from Simak ibn Harb, from al-Nu’man ibn Bashir, that the Prophet, may Allah bless him and grant him peace—and Surayj said in his narration: I heard the Prophet, may Allah bless him and grant him peace, saying: "The likeness of the believer is like the body; if a part of it aches, the rest of it suffers."