Sunan Ibn Majah Book 25, Hadith 43
“Which actions are best?” He said: “Raising one’s
voice and slaughtering the sacrificial animal.”
“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.’”
“There is no Muhrim (pilgrim in Ihram) who exposes himself to the sun all day for the sake of Allah, reciting the Talbiyah until the sun goes down, but his sins will disappear and he will go back like on the day his mother bore him.”