Musnad Ahmad 30:155

Sufyan narrated to us, from al-Zuhri, from Hanzala al-Aslami, who heard Abu Hurayrah saying: The Messenger of Allah (peace and blessings of Allah be upon him) said: "By the One in whose hand is the soul of Muhammad, the son of Maryam shall certainly pronounce the Talbiyah (saying 'Labbayk') in the mountain pass of al-Rawha', as a pilgrim performing Hajj, or as a pilgrim performing 'Umrah, or as both of them together."