[Al-Bukhari and Muslim].
Another narration adds: Abu Musa Al-Ash'ari (May Allah be pleased with him) said: The Prophet (ﷺ) ordered me to guard the door. When 'Uthman was told (about the misfortune) he praised Allah then said: "Allahu Musta'an (His help is to be sought)."
(The interpretation of Sa'id bin Al-Musaiyab is that the graves of Abu Bakr and 'Umar (May Allah be pleased with them) are by the side of the Prophet (ﷺ), in the same position they took when they sat next to the Prophet (ﷺ) while the grave of 'Uthman is away from their graves, in the public graveyard of Al-Madinah known as Baqi' Al-Gharqad).
وزاد في رواية: “وأمرني رسول الله صلى الله عليه وسلم بحفظ الباب. وفيها أن عثمان حين بشره حمد الله تعالى، ثم قال: الله المستعان.
Reference | : Riyad as-Salihin 708 |
In-book reference | : Book 1, Hadith 29 |