Sayyiduna Abu Hurayrah (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "Your day of fasting is the day on which you fast, and your day of sacrifice is the day on which you sacrifice."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8208