Volume 2 · Book 26 · Hadith 620
Narrated Anas: The Prophet offered four Rakat of the Zuhr prayer in Medina and two Rakat of the 'Asr prayer in Dhul-Hulaifa and I heard them (the companions of the Prophet) reciting Talbiya together loudly to the extent of shouting.
— Sahih Bukhari, Volume 2, Book 26: Pilgrimmage (Hajj), Hadith #620