Hadithcore
Sahih al-Bukhari, 4124
sahih

Al-Bara' bin `Azib said (through another chain of sub-narrators):

"On the day of Quraiza's (siege), Allah's Messenger (ﷺ) said to Hassan bin Thabit, 'Abuse them (with your poems), and Jibril is with you.'"

وَزَادَ إِبْرَاهِيمُ بْنُ طَهْمَانَ عَنِ الشَّيْبَانِيِّ، عَنْ عَدِيِّ بْنِ ثَابِتٍ، عَنِ الْبَرَاءِ بْنِ عَازِبٍ، قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَوْمَ قُرَيْظَةَ لِحَسَّانَ بْنِ ثَابِتٍ ‏

‏ اهْجُ الْمُشْرِكِينَ، فَإِنَّ جِبْرِيلَ مَعَكَ ‏

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References2 variants
In-Book Reference
Book 64, Hadith 168
USC-MSA web (English) reference
Vol. 1, Book 59, Hadith 449 (deprecated numbering scheme)