Riyad as-Salihin, Book 16, Hadith 1446 (In-Book) ⓘ

Hudhaifah and Abu Dharr (May Allah be pleased with him) reported: Whenever the Messenger of Allah went to bed, he would supplicate: "Bismika-Allahumma amut wa ahya (With Your Name, O Allah, I die and return to life)"; and when he woke up, he would supplicate thus: "Al-hamdu lillahilladhi ahyana ba'da ma amatana, wa ilaihin-nushur (All praise belongs to Allah Who has restored us back to life after causing us to die; and to Him shall we return)." [Al-Bukhari]

عن حذيفة، وأبي ذر رضي الله عنهما قالا‏:‏ كان رسول الله صلى الله عليه وسلم إذا أوى إلى فراشه قال‏:‏ ‏"‏باسمك اللهم أموت وأحيا‏"‏ وإذا استيقظ قال‏:‏ ‏"‏الحمد لله الذي أحيانا بعد ما أماتنا وإليه النشور‏"‏ ‏(‏‏(‏رواه البخاري‏)‏‏)‏‏.‏