Reference : Hisn al-Muslim 233

لَبَّيْكَ اللَّهُمَّ لَبَّيْكَ، 
لَبَّيْكَ لاَ شَرِيكَ لَكَ لَبَّيْكَ، 
إِنَّ الْحَمْدَ والنِّعْمَة لَكَ والمُلْكُ، 
لَا شَرِيكَ لَكَ
Labbayk-Allāhumma labbayk, 
labbayka lā sharīka laka labbayk,
inna ‘l-ḥamda, wanni`mata, laka wa ‘l-mulk, 
lā sharīka lak.


I am here at Your service, O Allah, I am here at Your service. 
I am here at Your service, You have no partner, I am here at Your service. 
Surely the praise, and blessings are Yours, and the dominion. 
You have no partner.

Reference:
Al-Bukhari, cf. Al-Asqalani, Fathul-Bari 3/408, Muslim 2/841.

Chapter: The Talbiya for the one doing Hajj or 'Umrah