Full Sharh — Riyad as-Salihin 767
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)).
English Translation
Hudhaifah and Abu Dharr (May Allah be pleased with him) reported:: Whenever the Messenger of Allah (ﷺ) 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)."
Source
Riyad as-Salihin(رياض الصالحين)
The Book of the Remembrance of Allah
Hadith Number
767