Sahih al-Bukhari — Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi) — Hadith No: 4451
Translation
Narrated `Aisha:The Prophet (ﷺ) expired in my house and on the day of my turn, leaning against my chest. One of us (i.e. the Prophet's wives ) used to recite a prayer asking Allah to protect him from all evils when he became sick. So I started asking Allah to protect him from all evils (by reciting a prayer ). He raised his head towards the sky and said, "With the highest companions, with the highest companions." `Abdur- Rahman bin Abu Bakr passed carrying a fresh leaf-stalk of a date-palm and the Prophet (ﷺ) looked at it and I thought that the Prophet (ﷺ) was in need of it (for cleaning his teeth ). So I took it (from `Abdur Rahman) and chewed its head and shook it and gave it to the Prophet (ﷺ) who cleaned his teeth with it, in the best way he had ever cleaned his teeth, and then he gave it to me, and suddenly his hand dropped down or it fell from his hand (i.e. he expired). So Allah made my saliva mix with his saliva on his last day on earth and his first day in the Hereafter