Amr bin Dinar (may Allah have mercy on him) says: I heard Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) saying takbir on the day of departure (from Mina), and he would order the people around him to say takbir. I do not know whether he was interpreting this saying of Allah, Lord of Might:
"And remember Allah during the numbered days." [Surah al-Baqarah: 203]
or the saying of Allah: "When you have completed your rites." [Surah al-Baqarah: 200]
Abd al-Hamid bin Abi Rabah (may Allah have mercy on him) narrates from a man who narrates from Sayyiduna Zayd bin Thabit (may Allah be pleased with him) that he used to say takbir from Zuhr on the Day of Sacrifice until the last of the days of Tashriq.
Ata bin Abi Rabah (may Allah have mercy on him) says: The imams would begin the takbirs from the Zuhr prayer on the Day of Sacrifice and continue saying takbir until the last of the days of Tashriq.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة العيدين / 6270