It is related from Ebrahim bin Muhammad (Radiallahu anhu) who is from the sons (grand sons of Ali radiallahu anhu, that whenever Ali radiallahu anhu described the noble features of Rasulullah (Sallallahu alaihe wasallam), he used to say:
"Rasulullah (Sallallahu alaihe wasallam) was neither very tall nor short, but of a medium stature among people. His hair was neither very curly nor very straight, but had a slight wave in it. He did not have a big body nor a round face, but his mubaarak face was slightly round (meaning he did not have a fully round face nor a fully elongated face, bur in between the two). The complexion of Rasulullah (Sallallahu alaihe wasallam) was white with redness in it. The mubaarak eyes of Rasulullah (Sallallahu alaihe wasallam) were extremely black. His eyelashes were long. The joints of the body (e.g. elbows and knees etc.) were large, likewise the portion between the two shoulders was broad and fully fleshed. There was no hair (more than normal) on his body. (Some people have profuse hair on their body. Sayyidina Rasulullah (Sallallahu alaihe wasallam) did not have hair on the parts of his body, besides places like the arms and legs etc.) He had a thin line of hair running from the chest to the navel. The hands and feet of Rasulullah (Sallallahu alaihe wasallam) were fully fleshed. When he walked, he lifted his legs with vigor, as if he were descending to a low-lying place. When he addressed a person he turned his whole body towards that person. (He did not only turn his face towards the person he addressed, as this is considered impolite, and sometimes, it even denotes pride. Sayyidina Rasulullah (Sallallahu alaihe wasallam) faced the person he spoke to, with his chest and body. Some scholars have translated this as, when Sayyidina Rasulullah (Sallallahu alaihe wasallam) addressed someone, he completely turned his face towards that person, and did not give a side glance. This is not a suitable translation). The seal of prophethood was situated between his shoulders. He was a last of all prophets. He was the most generous and the most truthful. He was the most kind-hearted and came from a most noble family. (It means his character, family back-ground and everything else was of the best). Any person who saw him suddenly would become awe-inspired. Sayyidina Rasulullah (Sallallahu alaihe wasallam) had such a great personality and dignity, that the person who saw him for the first time, because of his awe-inspiring personality, would be overcome with a feeling of profound respect. Firstly, there is a ro`b (awe) for physical beauty, with this when other Kamaalat are added what more could then be said of the ro'b (awe). Besides, the special attributes and qualities granted to Sayyidina Rasulullah (Sallallahu alaihe wasallam) ro'b (awe) is also one of the special qualities granted to him). Anyone who came in close contact with him, and knew his excellent character was smitten with the love of his excellent attributes. Anyone who described his noble features can only say: "I have not seen anyone like Rasulullah (Sallallahu alaihe wasallam) neither before nor after him."
حَدَّثَنَا أَحْمَدُ بْنُ عَبْدَةَ الضَّبِّيُّ الْبَصْرِيُّ، وَعَلِيُّ بْنُ حُجْرٍ، وَأَبُو جَعْفَرٍ مُحَمَّدُ بْنُ الْحُسَيْنِ وَهُوَ ابْنُ أَبِي حَلِيمَةَ، وَالْمَعْنَى وَاحِدٌ، قَالُوا‏:‏ حَدَّثَنَا عِيسَى بْنُ يُونُسَ، عَنْ عُمَرَ بْنِ عَبْدِ اللهِ مَوْلَى غُفْرَةَ، قَالَ‏:‏ حَدَّثَنِي إِبْرَاهِيمُ بْنُ مُحَمَّدٍ مِنْ وَلَدِ عَلِيِّ بْنِ أَبِي طَالِبٍ، قَالَ‏:‏ كَانَ عَلِيٌّ إِذَا وَصَفَ رَسُولَ اللهِ صلى الله عليه وسلم، قَالَ‏:‏ لَمْ يَكُنْ رَسُولُ اللهِ صلى الله عليه وسلم بِالطَّوِيلِ الْمُمَّغِطِ، وَلا بِالْقَصِيرِ الْمُتَرَدِّدِ، وَكَانَ رَبْعَةً مِنَ الْقَوْمِ، لَمْ يَكُنْ بِالْجَعْدِ الْقَطَطِ، وَلا بِالسَّبْطِ، كَانَ جَعْدًا رَجِلا، وَلَمْ يَكُنْ بِالْمُطَهَّمِ، وَلا بِالْمُكَلْثَمِ، وَكَانَ فِي وَجْهِهِ تَدْوِيرٌ، أَبْيَضُ مُشَرَبٌ، أَدْعَجُ الْعَيْنَيْنِ، أَهْدَبُ الأَشْفَارِ، جَلِيلُ الْمُشَاشِ وَالْكَتَدِ، أَجْرَدُ، ذُو مَسْرُبَةٍ، شَثْنُ الْكَفَّيْنِ وَالْقَدَمَيْنِ، إِذَا مَشَى كَأَنَّمَا يَنْحَطُّ فِي صَبَبٍ، وَإِذَا الْتَفَتَ الْتَفَتَ مَعًا، بَيْنَ كَتِفَيْهِ خَاتَمُ النُّبُوَّةِ، وَهُوَ خَاتَمُ النَّبِيِّينَ، أَجْوَدُ النَّاسِ صَدْرًا، وَأَصْدَقُ النَّاسِ لَهْجَةً، وَأَلْيَنُهُمْ عَرِيكَةً، وَأَكْرَمُهُمْ عِشْرَةً، مَنْ رَآهُ بَدِيهَةً هَابَهُ، وَمَنْ خَالَطَهُ مَعْرِفَةً أَحَبَّهُ، يَقُولُ نَاعِتُهُ‏:‏ لَمْ أَرَ قَبْلَهُ، وَلا بَعْدَهُ مِثْلَهُ صلى الله عليه وسلم‏.‏
English reference : Book 1, Hadith 6
Arabic reference : Book 1, Hadith 7