Musnad Ahmad

Abdur Rahman bin Yazid says that I was in the plain of Muzdalifah with Sayyiduna Ibn Mas'ud (may Allah be pleased with him). He performed two prayers, each prayer with a single adhan and iqamah, and ate food between the two. He performed the Fajr prayer when dawn had broken (or the narrator said that some people were saying that true dawn had appeared and some were saying that it had not yet appeared). Then he narrated this statement of the Prophet (peace and blessings be upon him): "Only at this place has the time of these two prayers been changed. People come to Muzdalifah at night, and the Fajr prayer should be performed at this time."