Sunan Ibn Majah Book 25, Hadith 41
“Jibra’il came to me and told me
to
command my Companions to raise their voices when reciting the
Talbiyah.”
“There is no (pilgrim) who recites the Talbiyah but that which is to his right and left also recites it, rocks and trees and hills, to the farthest ends of the earth in each direction, from here and from there.”
“Jibril came to me and said: ‘O Muhammad! Tell your Companions to raise their voices when reciting the Talbiyah, for it is one of the symbols of Hajj.’”