Supplication to be recited at the sacred area of Muzdalifah

 238. The Prophet (SAW) rode his camel, Al-Qaswa', until he reached the sacred area (Al-Mash'aril-Haraam). Then he faced the Qiblah and invoked Allah, and repeatedly said the words: Allaahu 'Akbar (Allah is the Most Great), Allaahu 'Ahad (Allah is One) and Laa 'ilaaha 'illallaah (There is none worthy of worship but Allah). He remained stationary until the sky became yellow with the dawn, and then pressed on before sunrise.

Reference: Muslim 2/891.