Sahih al-Bukhari 4955
Narrated Aisha:
The commencement of the Divine Inspiration to Allah's Messenger (ﷺ) was in the form of true dreams. The 
Angel came to him and said, "Read, in the Name of your Lord Who has created (all that exists), has 
created man a clot. Read! And your Lord is Most Generous" ..(96.1,2,3)
حَدَّثَنَا ابْنُ بُكَيْرٍ، حَدَّثَنَا اللَّيْثُ، عَنْ عُقَيْلٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ، أَنَّ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ أَوَّلُ مَا بُدِئَ بِهِ رَسُولُ اللَّهِ صلى الله عليه وسلم الرُّؤْيَا الصَّالِحَةُ فَجَاءَهُ الْمَلَكُ فَقَالَ ‏{‏اقْرَأْ بِاسْمِ رَبِّكَ الَّذِي خَلَقَ * خَلَقَ الإِنْسَانَ مِنْ عَلَقٍ * اقْرَأْ وَرَبُّكَ الأَكْرَمُ‏}‏