Musnad Ahmad 907:197

Husayn ibn Ali narrated to us, from Za'idah, from Simak, from Jabir ibn Samurah, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) used to recite in the Fajr prayer 'Qaf. By the Glorious Qur'an,' and his prayers after that were light. And the Messenger of Allah (peace and blessings of Allah be upon him), when he prayed Fajr, would sit in his place of prayer until the sun rose."