Sayyiduna Jabir (may Allah be pleased with him) said: People saw a fire in the graveyard, so they came to it, and saw that he (peace and blessings be upon him) was in the grave, saying: "Hand me your companion." And it was the man who used to raise his voice while remembering Allah.
It is narrated from Sayyiduna Abu Dharr (may Allah be pleased with him) that this was at night, and he (peace and blessings be upon him) had a lamp with him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6910