Ali bin Abi Talhah narrates from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) concerning the saying of Allah Almighty, "and offer sacrifice" [Surah al-Kawthar: 2], that it means: Slaughter on the Day of Sacrifice.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19005