Musnad Ahmad 1009:1

Abdullah narrated to us, Muhammad ibn Abi Bakr al-Muqaddami narrated to us, Humayd ibn al-Aswad narrated to us, al-Dahhak ibn Uthman narrated to us, from al-Maqburi, from Safwan ibn al-Mu'attal al-Sulami, that he asked the Prophet, peace and blessings of Allah be upon him, and said: "O Prophet of Allah, I ask you about that which you have knowledge of and I am ignorant of: is there an hour of the night or day in which prayer is disliked?" The Messenger of Allah, peace and blessings of Allah be upon him, said: "When you have prayed the morning prayer, refrain from prayer until the sun rises. When it rises, pray, for the prayer is witnessed and accepted until it is directly above your head like a spear. When it is directly above your head, that is an hour in which Hell is stoked and its gates are opened, until it moves away from your right eyebrow. When it moves away from your right eyebrow, pray, for the prayer is witnessed and accepted until you pray the afternoon prayer."