Whenever the Prophet ﷺ went to sleep, he would say, "O Allah, in Your name I live and die." When he woke up, he would say, "Praise be to Allah who has given us life after causing us to die, and to Him is the resurrection."
حدثنا أبو بكر بن أبي شيبة حدثنا وكيع عن سفيان عن عبد الملك بن عمير عن ربعي
كان النبي ﷺ إذا نام قال اللهم باسمك أحيا وأموت وإذا استيقظ قال الحمد لله الذي أحيانا بعدما أماتنا وإليه النشور
Bukhari, book of Supplications, chapter on what one says when going to sleep, no. 6312, from the hadith of Sufyan Thawri, with this wording.