Sunan an-Nasa'i, Volume 2, Book 19, Hadith 1589 (DarusSalam) ⓘ
It was narrated that Anas bin Malik said: "The Messenger of Allah addressed us on the day of Al-Adha and went to two black and white rams and slaughtered them."
أَخْبَرَنَا إِسْمَاعِيلُ بْنُ مَسْعُودٍ، قَالَ حَدَّثَنَا حَاتِمُ بْنُ وَرْدَانَ، عَنْ أَيُّوبَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ خَطَبَنَا رَسُولُ اللَّهِ صلى الله عليه وسلم يَوْمَ أَضْحَى وَانْكَفَأَ إِلَى كَبْشَيْنِ أَمْلَحَيْنِ فَذَبَحَهُمَا .
also referenced under: Hadith 1588 (Reference) & Book 19, Hadith 33 (In-Book)