Sahih Bukhari
Holding Fast to the Quran and Sunnah
Volume: 009 / Book Number: 092 / Hadith Number: 442
Narrated 'Umar:
The Prophet said to me, "Someone came to me tonight from my Lord while I was in the 'Aqiq (valley), and said to me, "Offer prayer in this blessed valley and say: 'Labbaik' for the (performance of) 'Umra and Hajj."