Musnad Ahmad 27:705

Yahya narrated to us, from Ubaydullah, Nafi’ informed me, from Ibn Umar, who said: I learned the Talbiyah from the Messenger of Allah, may Allah bless him and grant him peace: "Labbayk Allahumma Labbayk, Labbayka 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.)