Sahih Bukhari Volume 2, Book 26, Hadith Number 735.

Narated By ‘Abdur-Rahman bin Yazid : ‘Abdullah;- performed the Hajj and we reached Al-Muzdalifa at or about the time of the ‘Isha’ prayer. He ordered a man to pronounce the Adhan and Iqama and then he offered the Maghrib prayer and offered two Rakat after it. Then he asked for his supper and took it, and then, I think, he ordered a man to pronounce the Adhan and Iqama (for the ‘isha’ prayer). (‘Amr, a sub-narrator said: The intervening statement ‘I think’, was said by the sub-narrator Zuhair) (i.e. not by ‘Abdu-Rahman). Then ‘Abdullah offered two Rakat of ‘Isha’ prayer. When the day dawned, ‘Abdullah said, “The Prophet never offered any prayer at this hour except this prayer at this time and at this place and on this day.” ‘Abdullah added, “These two prayers are shifted from their actual times… the Maghrib prayer (is offered) when the people reached Al-Muzdalifa and the Fajr (morning) prayer at the early dawn.” ‘Abdullah added, “I saw the Prophet doing that.”