Sahih al-Bukhari 4124
Sahih al-Bukhari · Book 64: Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi) · The return of the Prophet (saws) from Ahzab and his going out to Bani Quraiza
Al-Bara' bin `Azib said (through another chain of sub-narrators):
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 ".
"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.'"