Hadithcore
Sahih Muslim, 162 b
sahih

It is narrated on the the outhority of Anas b. Malik that the Messenger of Allah (ﷺ) said:

(the angels) came to me and took me to the Zamzam and my heart was opened and washed with the water of Zamzam and then I was left (at my place).

حَدَّثَنِي عَبْدُ اللَّهِ بْنُ هَاشِمٍ الْعَبْدِيُّ، حَدَّثَنَا بَهْزُ بْنُ أَسَدٍ، حَدَّثَنَا سُلَيْمَانُ بْنُ الْمُغِيرَةِ، حَدَّثَنَا ثَابِتٌ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏

‏ أُتِيتُ فَانْطَلَقُوا بِي إِلَى زَمْزَمَ فَشُرِحَ عَنْ صَدْرِي ثُمَّ غُسِلَ بِمَاءِ زَمْزَمَ ثُمَّ أُنْزِلْتُ ‏

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References2 variants
In-Book Reference
Book 1, Hadith 317
USC-MSA web (English) reference
Book 1, Hadith 310 (deprecated numbering scheme)