Musnad Ahmad 27:637

Isma'il ibn Ibrahim narrated to us, Ayyub informed us, from Nafi', from Ibn 'Umar, that the Talbiyah of the Prophet, peace and blessings of Allah be upon him, was: "Labbayk Allahumma Labbayk, Labbayk la sharika laka Labbayk, inna al-hamda wa an-ni'mata laka wa al-mulk, la sharika lak." (At Your service, O Allah, at Your service. At Your service, You have no partner, at Your service. Indeed, all praise and grace are Yours, and the dominion; You have no partner.)