Maliks Muwatta Book 20, Hadith Number 49.

Yahya related to me from Malik, from Yahya ibn Said, that Umar ibn Abd alAziz was once going from Mina (to Arafa) on the day of Arafa and heard the takbir being said loudly, so he sent the guard to shout out to the people, “O people, you should be saying the talbiya.”