Musannaf Ibn Abi Shaybah 4977 — People who forget the prayer or sleep

Ata bin Yasar said that the Prophet (peace and blessings be upon him) prayed the two sunnah rak'ahs of Fajr after crossing the valley. Then he ordered Sayyiduna Bilal (may Allah be pleased with him); he called the adhan and the iqamah, and then he prayed the obligatory prayer.