It is narrated from Ibn Shihab that Umar bin Abdul Aziz (may Allah have mercy on him) was sitting on the pulpit when he delayed the prayer a little. So Urwah bin Zubair said that indeed Jibreel (peace be upon him) informed Muhammad (peace and blessings be upon him) about the timings of the prayer. So Umar (may Allah be pleased with him) said, "Be sure of what you are saying." Urwah said, "I heard Bashir bin Abi Mas'ud saying that I heard Abu Mas'ud Ansari (may Allah be pleased with him) say, 'I heard the Messenger of Allah (peace and blessings be upon him) say: Jibreel (peace be upon him) descended and informed me of the timings of the prayer, so I prayed with him, then I prayed with him again, then I prayed with him, then I prayed with him.' He counted five prayers on his fingers. And I saw the Messenger of Allah (peace and blessings be upon him) perform the Zuhr prayer when the sun had declined, and sometimes he would delay it when the heat was intense. And I saw him perform the Asr prayer when the sun was high and white, before it turned yellow. So a person would finish the prayer and reach Dhul-Hulaifah before sunset. And the Messenger of Allah (peace and blessings be upon him) would perform the Maghrib prayer at the time of sunset, and the Isha prayer when the horizon became dark, and sometimes he would delay it until the people gathered. Once, he delayed the Fajr prayer until the people gathered in the darkness. Once, he performed the Fajr prayer in darkness, then another time he performed it in brightness, then after that his prayer would be in darkness until he passed away. After that, he never performed the prayer in brightness. Imam Abu Bakr (may Allah have mercy on him) said that this addition in the narration was only mentioned by Usamah bin Zaid, the narrator. In this entire hadith, there is evidence that the meaning of "shafaq" is whiteness, not redness. Because in the hadith it is mentioned that the Messenger of Allah (peace and blessings be upon him) would perform the Isha prayer when the horizon became dark. And the horizon becomes dark when the whiteness that appears after the redness disappears. Because when the redness ends, the whiteness remains after it, then when the whiteness disappears, the horizon becomes dark. And in the narration of Jabir bin Abdullah (may Allah be pleased with him), it is mentioned that Bilal (may Allah be pleased with him) gave the adhan for Isha when the whiteness of the day ended, so the Prophet (peace and blessings be upon him) ordered him, so he gave the iqamah for the prayer, then the Prophet (peace and blessings be upon him) led the prayer.