From Sahih Bukhari (Hadith 6152):
Narrated Abu Salama bin `Abdur-Rahman bin `Auf:that he heard Hassan bin Thabit Al-Ansari asking the witness of Abu Huraira, saying, "O Abu- Huraira! I beseech you by Allah (to tell me). Did you hear Allah's Messenger (ﷺ) saying' 'O Hassan ! Reply on behalf of Allah's Messenger (ﷺ). O Allah ! Support him (Hassan) with the Holy Spirit (Gabriel).'?" Abu Huraira said, "Yes
Reference: Bukhari 6152