It is narrated from Sayyiduna Abu Rafi' (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) went out in the middle of the night to supplicate at al-Baqi', and Sayyiduna Abu Rafi' (may Allah be pleased with him) was with him. He (peace and blessings be upon him) supplicated as much as Allah willed, then turned to go back. He passed by a grave and said: "Uff, uff, uff." Abu Rafi' (may Allah be pleased with him) said: O Prophet of Allah! May my father and mother be sacrificed for you, there is no one with you except me; was it because of me that you said 'uff'? The Messenger of Allah (peace and blessings be upon him) said: "No, rather I said it because of the occupant of this grave, who was asked about me and he doubted concerning me."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 957