The Book of Jihad, Military Expeditions, and Authority-06b

The reciter: Isma'il ibn Ibrahim narrated to us, Sufyan informed us, from al-Aswad ibn Qays, that he heard Jundub saying: أَبْطَأَ جِبْرِيلُ عَلَى رَسُولِ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ، فَقَالَ الْمُشْرِكُونَ : قَدْ وُدِّعَ مُحَمَّدٌ، فَأَنْزَلَ اللهُ عَزَّ وَجَلَّ : وَالضُّحَى وَاللَّيْلِ إِذَا سَجَى مَا وَدَّعَكَ رَبُّكَ وَمَا قَلَى Gabriel was delayed with the Messenger of Allah (peace and blessings be upon him), so the polytheists said: "Muhammad has been forsaken." So Allah, Mighty and Majestic, revealed: "By the morning brightness, and by the night when it is quiet, your Lord has not forsaken you, nor has He become angry.".

The Shaykh : The morning brightness is the beginning of the day, in which the light is bright and all-encompassing.
, this light covers it, so Allah the Exalted swore by two opposing things: the whiteness of the day and the darkness of the night.
means He did not leave you and He did not become angry with you, because He, Mighty and Majestic, loves you, and the delay of the revelation was for one of the reasons.