Musannaf Ibn Abi Shayba 8:837

Abu Bakr narrated to us, he said: Ibn Idris narrated to us, from Yahya and Ubayd Allah, from Nafi’, from Ibn Umar, who said: I received them from the mouth of the Messenger of Allah, may Allah bless him and grant him peace: "Labbayk Allahumma Labbayk. Labbayk, la sharika laka Labbayk. Inna al-hamda wa an-ni’mata laka wa al-mulk, la sharika lak." (I am present, O Allah, I am present. I am present, there is no partner for You, I am present. Indeed, all praise and grace are Yours, and the dominion; there is no partner for You.) He said: And Ibn Umar used to add: "War-raghba'u ilayka wal-'amal. Labbayk wa sa'dayk." (And the longing is toward You, and the deed. I am present and ready to serve You.)