Musnad Ahmad 974:1

'Abd al-Samad narrated to us, Aban narrated to us, Abu 'Imran narrated to us, Zuhayr ibn 'Abd Allah—who was a governor over Tawwaj, and he praised him well—narrated to us, from some of the companions of the Prophet, may Allah bless him and grant him peace, from the Prophet, may Allah bless him and grant him peace, that he said: "Whoever sleeps on a roof that has no barrier to protect his feet, and he falls, then the covenant [of protection] is absolved from him. And whoever boards the sea when it is turbulent, then the covenant [of protection] is absolved from him."