Ash-Shama'il Al-Muhammadiyah, Book 55, Hadith 392 (English) ⓘ

Kulayb bin Shihaab Al-Kufi says that Abu Hurayrah Radiyallahu 'Anhu narrated to me the mubaarak saying of Rasulullah Sallallahu 'Alayhi Wasallam, that whomsoever sees me in a dream, has really seen me, because the shaytaan cannot impersonate me. Kulayb says, I mentioned this hadith to Ibn 'Abbaas Radiyallahu 'Anhu and also told him that I was blessed with the seeing of Rasulullah Sallallahu 'Alayhi Wasallam in my dream. At that moment I thought of Hasan bin 'Ali Radiyallahu 'Anhu. I said to Ibn 'Abbaas Radiyallahu 'Anhu that I found the image in my dream very similar to that of Hasan Radiyallahu 'Anhu. Ibn 'Abbaas Radiyallahu 'Anhu verified my statement, that truly Hasan Radiyallahu 'Anhu was very similar to Rasulullah Sallallahu 'Alayhi Wasallam in appearance.

حَدَّثَنَا قُتَيْبَةُ هُوَ ابْنُ سَعِيدٍ، قَالَ‏:‏ حَدَّثَنَا عَبْدُ الْوَاحِدِ بْنُ زِيَادٍ، عَنْ عَاصِمِ بْنِ كُلَيْبٍ، قَالَ‏:‏ حَدَّثَنِي أَبِي، أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ، يَقُولُ‏:‏ قَالَ رَسُولُ اللهِ صلى الله عليه وسلم‏:‏ مَنْ رَآنِي فِي الْمَنَامِ فَقَدْ رَآنِي، فَإِنَّ الشَّيْطَانَ لا يَتَمَثَّلُنِي، قَالَ أَبِي‏:‏ فَحَدَّثْتُ بِهِ ابْنَ عَبَّاسٍ، فَقُلْتُ‏:‏ قَدْ رَأَيْتُهُ، فَذَكَرْتُ الْحَسَنَ بْنَ عَلِيٍّ، فَقُلْتُ‏:‏ شَبَّهْتُهُ بِهِ، فَقَالَ ابْنُ عَبَّاسٍ‏:‏ إِنَّهُ كَانَ يُشْبِهُهُ‏.‏