Musnad Ahmad 27:1561

Ali ibn Ishaq narrated to us, Abdullah narrated to us, Yunus informed us, from al-Zuhri, from Salim, from Abdullah ibn Umar, who said: I heard the Messenger of Allah, may Allah bless him and grant him peace, while he was in the state of *talbiyah* with his hair matted, saying: "Labbayk Allahumma Labbayk, Labbayk la sharika laka Labbayk, inna al-hamda wa an-ni'mata laka wa al-mulk, la sharika lak." He would not add to these words.