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."
Muwatta Malik Book 20, Hadith 50