Sunan Abi Dawud, Hadith 2784 ⓘ
Narrated Hanash: I saw Ali sacrificing two rams; so I asked him: What is this? He replied. The Messenger of Allah enjoined upon me to sacrifice on his behalf, so that is what I am doing.
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا شَرِيكٌ، عَنْ أَبِي الْحَسْنَاءِ، عَنِ الْحَكَمِ، عَنْ حَنَشٍ، قَالَ رَأَيْتُ عَلِيًّا يُضَحِّي بِكَبْشَيْنِ فَقُلْتُ مَا هَذَا فَقَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم أَوْصَانِي أَنْ أُضَحِّيَ عَنْهُ فَأَنَا أُضَحِّي عَنْهُ .
also referenced under: Hadith 2790 (DarusSalam) & Book 15, Hadith 2784 (USC-MSA)