لَبَّيْكَ اَللَّهمَّ بِحَجَّةٍ (لَبَّيْكَ حَجًّا)

Labbaika allaahumma bihajjah (labbaika hajja)

O Allah! I am present for the purpose of Hajj.

Reference: Manasikul Hajj, Albani, 16 p.