Musannaf Ibn Abi Shayba 3:3270

Yazid ibn Harun narrated to us, he said: Ibn Abi Dhi'b narrated to us, from al-Zuhri, that the Messenger of Allah (may Allah bless him and grant him peace) used to say the takbir from the Dhuhr prayer on the Day of Arafah until the Asr prayer of the last of the days of Tashriq.