Sunan an-Nasa'i, Book 43, Hadith 58 (In-Book) ⓘ

It was narrated that Anas bin Malik told them that: the Prophet sacrificed two Amlah horned rams, putting his foot on their sides and slaughtering them pronouncing the name of Allah, and saying: Allahu Akbar."" (Sahih )

أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا يَزِيدُ، - يَعْنِي ابْنَ زُرَيْعٍ - قَالَ حَدَّثَنَا سَعِيدٌ، قَالَ حَدَّثَنَا قَتَادَةُ، أَنَّ أَنَسَ بْنَ مَالِكٍ، حَدَّثَهُمْ أَنَّ نَبِيَّ اللَّهِ صلى الله عليه وسلم ضَحَّى بِكَبْشَيْنِ أَقْرَنَيْنِ أَمْلَحَيْنِ يَطَؤُ عَلَى صِفَاحِهِمَا وَيَذْبَحُهُمَا وَيُسَمِّي وَيُكَبِّرُ ‏.‏