Musannaf Ibn Abi Shayba 21:177

Ubaydah ibn Humayd narrated to us, from Abd al-Malik ibn Umayr, from Rib'i ibn Hirash, from Hudhayfah, who said: When the Prophet, peace and blessings of Allah be upon him, would take to his bed, he would say: "O Allah, in Your name I die and I live." And when he would wake up, he would say: "Praise be to Allah who gave us life after He caused us to die, and to Him is the resurrection."