Yazeed Al Faarisi bin Hurmuz, who was a calligrapher of the Qur-aan, once saw Rasulullah (صلی اللہ علیہ وسلم) in his dream during the time of Ibn 'Abbaas Radiyallahu 'Anhu. He related his dream to Ibn 'Abbaas. Ibn 'Abbaas said:
إِنَّ رَسُولَ اللهِ كَانَ، يَقُولُ: إِنَّ الشَّيْطَانَ لا يَسْتَطِيعُ أَنْ يَتَشَبَّهَ بِي، فَمَنْ رَآنِي فِي النَّوْمِ فَقَدْ رَآنِي، هَلْ تَسْتَطِيعُ أَنْ تَنْعَتَ هَذَا الرَّجُلَ الَّذِي رَأَيْتَهُ فِي النَّوْمِ؟
"Rasulullah (صلی اللہ علیہ وسلم) used to say that the shaytaan cannot imitate him. That person who has seen him in a dream has really seen him'. After mentioning this he asked: 'Can you describe this person whom you have seen in your dream?'. I replied: ((apart of mentioning other things he said)).
مَلأَتْ لِحْيَتُهُ مَا بَيْنَ هَذِهِ إِلَى هَذِهِ، قَدْ مَلأَتْ نَحْرَهُ، قَالَ عَوْفٌ: وَلا أَدْرِي مَا كَانَ مَعَ هَذَا النَّعْتِ، فَقَالَ ابْنُ عَبَّاسٍ: لَوْ رَأَيْتَهُ فِي الْيَقَظَةِ مَا اسْتَطَعْتَ أَنْ تَنْعَتَهُ فَوْقَ هَذَا
A compact beard which surrounded his mubaarak face, and spread on the fore-portion of the chest". 'Awf ibn Abl Jamilah, a narrator of this hadith says: "I do not remember what other feature besides these, my ustaadh Yazeed, who is a narrator of this hadith, described". Ibn 'Abbaas Radiyallahu 'Anhu said: "If you had seen him while being awake, you would not have been able to describe him any further"
(ref: shumail-e-tirmidhi, hadeeth number: 393 the narration has come with authentic chain.)
One of the narrator of this narration yazeed al-farsi is hasan al-hadeeth Imaam hatim ar-raazi (رحمہ اللہ) narrate about him:
There is no issue in him
(al-jarha wa ta'deel volume: 9, page: 294)
Imaam tirmidhi, narrated this in sunan, hadeeth number: 3086, ibn hibbaan in raqam: 43, imaam haakim 2/221, 320 they all (رحمہم اللہ) graded one of the narration of yazeed al-farsi as authentic.
And this is tawtheeq (acceptance), Hafith dhahabi (رحمہ اللہ) agreed in it. Hadith haithami (رحمہ اللہ) graded as thaqqah to all of the narrators of this narration: majma' az-zawaid volume: 8 page: 272)
There are many of matters can be deduced from this authentic narration. Some of them are:
1. The beard of prophet (صلی اللہ علیہ وسلم) was so long that spread on the fore-portion of the chest, ma sha Allah.
2. If a person says that he saws prophet (صلی اللہ علیہ وسلم) in dreams then we must ask him that what kinda attributes you saw prophet (صلی اللہ علیہ وسلم). As of course shaytaan can not take the face of prophet (صلی اللہ علیہ وسلم) in dream but he can make up another person's shape and misguide people.
3. When you see a dream you can ask from a virtuous scholar about the meaning of the dream.
4. We should talk about prophet (صلی اللہ علیہ وسلم) and his authentic deeds.
and many more matters which ulamah can deduce from this narration.
We hope and pray and do give naseeha to our self and to our brothers and sisters in Islam to do read shamail-e-tirmidhi or shamail-e-muhammadi (both are the name of same book) and understand and grasp how our prophet (صلی اللہ علیہ وسلم) were in looks, in height, in a'maal, in good deeds, in practicing our deen etc.