Sunan an-Nasa'i 933
It was narrated that Aishah said:
"Al-Harith bin Hisham asked the Messenger of Allah (ﷺ): 'How does the Revelation come to you?' He said: 'Like the ringing of a bell, and when it departs I remember what he (the Angel) said, and this is the hardest on me. And sometimes he (the Angel) comes to me in the form of a man and gives it to me.'"
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا سُفْيَانُ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ سَأَلَ الْحَارِثُ بْنُ هِشَامٍ رَسُولَ اللَّهِ صلى الله عليه وسلم كَيْفَ يَأْتِيكَ الْوَحْىُ قَالَ ‏
"‏ فِي مِثْلِ صَلْصَلَةِ الْجَرَسِ فَيَفْصِمُ عَنِّي وَقَدْ وَعَيْتُ وَهُوَ أَشَدُّهُ عَلَىَّ وَأَحْيَانًا يَأْتِينِي فِي مِثْلِ صُورَةِ الْفَتَى فَيَنْبِذُهُ إِلَىَّ ‏"‏ ‏.‏