The last words he ﷺ said
Spoken as he was dying, with his hand raised.
اللَّهُمَّ فِي الرَّفِيقِ الأَعْلَى
Allāhumma fi-r-rafīqi-l-aʿlā.
“O Allah, with the highest Companion.”
Aisha said she knew then that he had been given the choice, and that he had chosen.
The full narration
Narrated Aisha:When Allah's Apostle was in good health, he used to say, "Never does a prophet die unless he is shown his place in Paradise ( before his death ), and then he is made alive or given the option." When the Prophet became ill and his last moments came while his head was on my thigh, he became unconscious, and when he came to his senses, he looked towards the roof of the house and then said, "O Allah! (Please let me be) with the highest companion." Thereupon I said, "Hence he is not going to stay with us?" Then I came to know that his state was the confirmation of the narration he used to mention to us while he was in good health
Source
Ṣaḥīḥ al-Bukhārī · 4437
- Agreed upon as authentic (al-Bukhārī / Muslim)