Yahya related to me from Malik from Abdullah ibn Dinar thatAbdullah ibn Umar said, "On one occasion when the people were prayingsubhat Quba a man came to them and said, 'A piece of Qur'an was sentdown to the Messenger of Allah, may Allah bless him and grant himpeace, last night, and he was ordered to face the Kaba, so face it.'They had been facing ash-Sham, so they turned round and faced theKaba.''
USC-MSA web (English) reference: Book 14, Hadith 6
Arabic reference: Book 14, Hadith 463