Sahih Muslim 1797a
It has been narrated on the authority of Aswad b. Qais who heard Jundub saying that Gabriel delayed his visit to the Messenger of Allah ﷺ The polytheists began to say that Muhammad has been forsaken. At this Allah, the Glorious and Exalted, revealed:" Wa'dd hd wa'l-laili iza saja, ma wadda'ka Rabbuka wa' ma qala" [By the glorious morning light, and by the night when it is still: thy Lord has not forsaken thee, nor is He displeased].
حَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، أَخْبَرَنَا سُفْيَانُ، عَنِ الأَسْوَدِ بْنِ قَيْسٍ، أَنَّهُ سَمِعَ جُنْدُبًا، يَقُولُ أَبْطَأَ جِبْرِيلُ عَلَى رَسُولِ اللَّهِ ﷺ فَقَالَ الْمُشْرِكُونَ قَدْ وُدِّعَ مُحَمَّدٌ فَأَنْزَلَ اللَّهُ عَزَّ وَجَلَّ { وَالضُّحَى * وَاللَّيْلِ إِذَا سَجَى * مَا وَدَّعَكَ رَبُّكَ وَمَا قَلَى}