كتاب الحج
20  
Hajj

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."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، أَنَّ عُمَرَ بْنَ عَبْدِ الْعَزِيزِ، غَدَا يَوْمَ عَرَفَةَ مِنْ مِنًى فَسَمِعَ التَّكْبِيرَ عَالِيًا فَبَعَثَ الْحَرَسَ يَصِيحُونَ فِي النَّاسِ أَيُّهَا النَّاسُ إِنَّهَا التَّلْبِيَةُ ‏.‏
USC-MSA web (English) reference : Book 20, Hadith 49
Arabic reference : Book 20, Hadith 754