Sahih al-Bukhari 5994
Narrated Ibn Abi Na'm:
I was present when a man asked Ibn `Umar about the blood of mosquitoes. Ibn `Umar said, "From 
where are you?" The man replied. "From Iraq." Ibn `Umar said, "Look at that! he is asking me about 
the blood of Mosquitoes while they (the Iraqis ) have killed the (grand) son of the Prophet. I have 
heard the Prophet (ﷺ) saying, "They (Hasan and Husain) are my two sweet-smelling flowers in this 
world."
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا مَهْدِيٌّ، حَدَّثَنَا ابْنُ أَبِي يَعْقُوبَ، عَنِ ابْنِ أَبِي نُعْمٍ، قَالَ كُنْتُ شَاهِدًا لاِبْنِ عُمَرَ وَسَأَلَهُ رَجُلٌ عَنْ دَمِ الْبَعُوضِ‏.‏ فَقَالَ مِمَّنْ أَنْتَ فَقَالَ مِنْ أَهْلِ الْعِرَاقِ‏.‏ قَالَ انْظُرُوا إِلَى هَذَا، يَسْأَلُنِي عَنْ دَمِ الْبَعُوضِ وَقَدْ قَتَلُوا ابْنَ النَّبِيِّ صلى الله عليه وسلم وَسَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يَقُولُ ‏
"‏ هُمَا رَيْحَانَتَاىَ مِنَ الدُّنْيَا ‏"‏‏.‏