Abu Huraira reported that 'Umar happened to pass by Hassan as he was reciting verses in the mosque. He (Hadrat 'Umar) looked towards him (meaningfully), whereupon he (gassin) said:

I used to recite (verses) when one better than you (the Prophet) had been present (here). He then looked towards Abu Huraira and said to him: I adjure you by Allah (to tell) if you had not heard Allah's Messenger (ﷺ) as saying: (Hassan), give a reply on my behalf; Allah I help him with Ruh-ul-Qudus. He (Abu Huraira) said: By Allah, it is so (i. e. the Prophet (ﷺ) actually said these words).

حَدَّثَنَا عَمْرٌو النَّاقِدُ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ، وَابْنُ أَبِي عُمَرَ، كُلُّهُمْ عَنْ سُفْيَانَ، قَالَ عَمْرٌو حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنِ الزُّهْرِيِّ، عَنْ سَعِيدٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ عُمَرَ، مَرَّ بِحَسَّانَ وَهُوَ يُنْشِدُ الشِّعْرَ فِي الْمَسْجِدِ فَلَحَظَ إِلَيْهِ فَقَالَ قَدْ كُنْتُ أُنْشِدُ وَفِيهِ مَنْ هُوَ خَيْرٌ مِنْكَ ‏.‏ ثُمَّ الْتَفَتَ إِلَى أَبِي هُرَيْرَةَ فَقَالَ أَنْشُدُكَ اللَّهَ أَسَمِعْتَ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏

‏ أَجِبْ عَنِّي اللَّهُمَّ أَيِّدْهُ بِرُوحِ الْقُدُسِ ‏

‏ ‏.‏ قَالَ اللَّهُمَّ نَعَمْ ‏.‏