Narrated Aisha:

(the wife of the Prophet) The commencement (of the Divine Inspiration) to Allah's Messenger (ﷺ) was in the form of true dreams in his sleep, for he never had a dream but it turned out to be true and clear as the bright daylight. Then he began to like seclusions, so he used to go in seclusion in the cave of Hira where he used to worship Allah continuously for many nights before going back to his family to take the necessary provision (of food) for the stay. He come back to (his wife) Khadija again to take his provision (of food) likewise, till one day he received the Guidance while he was in the cave of Hira. An Angel came to him and asked him to read. Allah's Messenger (ﷺ) replied, "I do not know how to read." The Prophet (ﷺ) added, "Then the Angel held me (forcibly) and pressed me so hard that I felt distressed. Then he released me and again asked me to read, and I replied, 'I do not know how to read.' Thereupon he held me again and pressed me for the second time till I felt distressed. He then released me and asked me to read, but again I replied. 'I do not know how to read.' Thereupon he held me for the third time and pressed me till I got distressed, and then he released me and said, 'Read, in the Name of your Lord Who has created (all that exists), has created man out of a clot, Read! And your Lord is the Most Generous. Who has taught (the writing) by the pen, has taught man that which he knew not." (96.1-5). Then Allah's Messenger (ﷺ) returned with that experience; and the muscles between his neck and shoulders were trembling till he came upon Khadija (his wife) and said, "Cover me!" They covered him, and when the state of fear was over, he said to Khadija, "O Khadija! What is wrong with me? I was afraid that something bad might happen to me." Then he told her the story. Khadija said, "Nay! But receive the good tidings! By Allah, Allah will never disgrace you, for by Allah, you keep good relations with your Kith and kin, speak the truth, help the poor and the destitute, entertain your guests generously and assist those who are stricken with calamities." Khadija then took him to Waraqa bin Naufil, the son of Khadija's paternal uncle. Waraqa had been converted to Christianity in the Pre-lslamic Period and used to write Arabic and write of the Gospel in Arabic as much as Allah wished him to write. He was an old man and had lost his eyesight. Khadija said (to Waraqa), "O my cousin! Listen to what your nephew is going to say." Waraqa said, "O my nephew! What have you seen?" The Prophet (ﷺ) then described whatever he had seen. Waraqa said, "This is the same Angel (Gabriel) who was sent to Moses. I wish I were young." He added some other statement. Allah's Messenger (ﷺ) asked, "Will these people drive me out?" Waraqa said, "Yes, for nobody brought the like of what you have brought, but was treated with hostility. If I were to remain alive till your day (when you start preaching). then I would support you strongly." But a short while later Waraqa died and the Divine Inspiration was paused (stopped) for a while so that Allah's Messenger (ﷺ) was very much grieved.

حَدَّثَنَا يَحْيَى، حَدَّثَنَا اللَّيْثُ، عَنْ عُقَيْلٍ، عَنِ ابْنِ شِهَابٍ، حَدَّثَنِي سَعِيدُ بْنُ مَرْوَانَ، حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ الْعَزِيزِ بْنِ أَبِي رِزْمَةَ، أَخْبَرَنَا أَبُو صَالِحٍ، سَلْمَوَيْهِ قَالَ حَدَّثَنِي عَبْدُ اللَّهِ، عَنْ يُونُسَ بْنِ يَزِيدَ، قَالَ أَخْبَرَنِي ابْنُ شِهَابٍ، أَنَّ عُرْوَةَ بْنَ الزُّبَيْرِ، أَخْبَرَهُ أَنَّ عَائِشَةَ زَوْجَ النَّبِيِّ صلى الله عليه وسلم قَالَتْ كَانَ أَوَّلُ مَا بُدِئَ بِهِ رَسُولُ اللَّهِ صلى الله عليه وسلم الرُّؤْيَا الصَّادِقَةُ فِي النَّوْمِ، فَكَانَ لاَ يَرَى رُؤْيَا إِلاَّ جَاءَتْ مِثْلَ فَلَقِ الصُّبْحِ، ثُمَّ حُبِّبَ إِلَيْهِ الْخَلاَءُ فَكَانَ يَلْحَقُ بِغَارِ حِرَاءٍ فَيَتَحَنَّثُ فِيهِ ـ قَالَ وَالتَّحَنُّثُ التَّعَبُّدُ ـ اللَّيَالِيَ ذَوَاتِ الْعَدَدِ قَبْلَ أَنْ يَرْجِعَ إِلَى أَهْلِهِ، وَيَتَزَوَّدُ لِذَلِكَ، ثُمَّ يَرْجِعُ إِلَى خَدِيجَةَ فَيَتَزَوَّدُ بِمِثْلِهَا، حَتَّى فَجِئَهُ الْحَقُّ وَهْوَ فِي غَارِ حِرَاءٍ فَجَاءَهُ الْمَلَكُ فَقَالَ اقْرَأْ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ مَا أَنَا بِقَارِئٍ ‏"‏‏.‏ قَالَ ‏"‏ فَأَخَذَنِي فَغَطَّنِي حَتَّى بَلَغَ مِنِّي الْجُهْدُ ثُمَّ أَرْسَلَنِي‏.‏ فَقَالَ اقْرَأْ‏.‏ قُلْتُ مَا أَنَا بِقَارِئٍ‏.‏ فَأَخَذَنِي فَغَطَّنِي الثَّانِيِةَ حَتَّى بَلَغَ مِنِّي الْجُهْدُ، ثُمَّ أَرْسَلَنِي‏.‏ فَقَالَ اقْرَأْ‏.‏ قُلْتُ مَا أَنَا بِقَارِئٍ‏.‏ فَأَخَذَنِي فَغَطَّنِي الثَّالِثَةَ حَتَّى بَلَغَ مِنِّي الْجُهْدُ ثُمَّ أَرْسَلَنِي‏.‏ فَقَالَ ‏{‏اقْرَأْ بِاسْمِ رَبِّكَ الَّذِي خَلَقَ * خَلَقَ الإِنْسَانَ مِنْ عَلَقٍ * اقْرَأْ وَرَبُّكَ الأَكْرَمُ * الَّذِي عَلَّمَ بِالْقَلَمِ‏}‏ ‏"‏‏.‏ الآيَاتِ إِلَى قَوْلِهِ ‏{‏عَلَّمَ الإِنْسَانَ مَا لَمْ يَعْلَمْ‏}‏ فَرَجَعَ بِهَا رَسُولُ اللَّهِ صلى الله عليه وسلم تَرْجُفُ بَوَادِرُهُ حَتَّى دَخَلَ عَلَى خَدِيجَةَ فَقَالَ ‏"‏ زَمِّلُونِي زَمِّلُونِي ‏"‏‏.‏ فَزَمَّلُوهُ حَتَّى ذَهَبَ عَنْهُ الرَّوْعُ قَالَ لِخَدِيجَةَ ‏"‏ أَىْ خَدِيجَةُ مَا لِي، لَقَدْ خَشِيتُ عَلَى نَفْسِي ‏"‏‏.‏ فَأَخْبَرَهَا الْخَبَرَ‏.‏ قَالَتْ خَدِيجَةُ كَلاَّ أَبْشِرْ، فَوَاللَّهِ لاَ يُخْزِيكَ اللَّهُ أَبَدًا، فَوَاللَّهِ إِنَّكَ لَتَصِلُ الرَّحِمَ، وَتَصْدُقُ الْحَدِيثَ، وَتَحْمِلُ الْكَلَّ، وَتَكْسِبُ الْمَعْدُومَ، وَتَقْرِي الضَّيْفَ، وَتُعِينُ عَلَى نَوَائِبِ الْحَقِّ‏.‏ فَانْطَلَقَتْ بِهِ خَدِيجَةُ حَتَّى أَتَتْ بِهِ وَرَقَةَ بْنَ نَوْفَلٍ وَهْوَ ابْنُ عَمِّ خَدِيجَةَ أَخِي أَبِيهَا، وَكَانَ امْرَأً تَنَصَّرَ فِي الْجَاهِلِيَّةِ، وَكَانَ يَكْتُبُ الْكِتَابَ الْعَرَبِيَّ وَيَكْتُبُ مِنَ الإِنْجِيلِ بِالْعَرَبِيَّةِ مَا شَاءَ اللَّهُ أَنْ يَكْتُبَ، وَكَانَ شَيْخًا كَبِيرًا قَدْ عَمِيَ فَقَالَتْ خَدِيجَةُ يَا ابْنَ عَمِّ اسْمَعْ مِنِ ابْنِ أَخِيكَ‏.‏ قَالَ وَرَقَةُ يَا ابْنَ أَخِي مَاذَا تَرَى فَأَخْبَرَهُ النَّبِيُّ صلى الله عليه وسلم خَبَرَ مَا رَأَى‏.‏ فَقَالَ وَرَقَةُ هَذَا النَّامُوسُ الَّذِي أُنْزِلَ عَلَى مُوسَى، لَيْتَنِي فِيهَا جَذَعًا، لَيْتَنِي أَكُونُ حَيًّا‏.‏ ذَكَرَ حَرْفًا‏.‏ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ أَوَمُخْرِجِيَّ هُمْ ‏"‏‏.‏ قَالَ وَرَقَةُ نَعَمْ لَمْ يَأْتِ رَجُلٌ بِمَا جِئْتَ بِهِ إِلاَّ أُوذِيَ، وَإِنْ يُدْرِكْنِي يَوْمُكَ حَيًّا أَنْصُرْكَ نَصْرًا مُؤَزَّرًا‏.‏ ثُمَّ لَمْ يَنْشَبْ وَرَقَةُ أَنْ تُوُفِّيَ، وَفَتَرَ الْوَحْىُ، فَتْرَةً حَتَّى حَزِنَ رَسُولُ اللَّهِ صلى الله عليه وسلم‏.‏
USC-MSA web (English) reference : Vol. 6, Book 60, Hadith 478
Arabic reference : Book 65, Hadith 4953