Zirr bin Jubaish reported from Ali [may Allah be pleased with him] that he said:
"We were still in doubt concerning the torment of the grave, until 'the mutual rivalry diverts you" was revealed'." (ID)
English reference (ID): Vol. 5, Book 44, Hadith 3355 (ID)
Arabic reference (ID): Book 47, Hadith 3680 (ID)