The Messenger of Allah [SAW] said: "Ten things are part of the Fitrah: Trimming the mustache, trimming the nails, washing the joints, letting the beard grow, using the Siwak, rinsing the nose, plucking the armpit hairs, shaving the pubes, and washing with water (after relieving oneself)." Mus'ab bin Shaibah said: "I have forgotten the tenth, unless it was rinsing the mouth."
"I heard Talq mentioning ten things that have to do with the Fitrah: Using the Siwak, trimming the mustache, clipping the nails, washing the joints, shaving the pubes, rinsing the nose, and I am not sure about rinsing the mouth."
"Ten things are from the Sunnah: Using the Siwak, trimming the mustache, rinsing the mouth, rinsing the nose, letting the beard grow, trimming the nails, plucking the armpit hairs, circumcision, shaving the pubes and washing one's backside."
"The Messenger of Allah [SAW] said: 'Five things are of the Fitrah: Circumcision, shaving the pubes, plucking the armpit hair, clipping the nails and trimming the mustache.'"
"Five things are of the Fitrah: Clipping the nails, trimming the mustache, plucking the armpit hairs, shaving the pubes, and circumcision." (Sahih Mawquf)
The Prophet [SAW] saw a boy, part of whose head had been shaven and part had been left. He forbade that and said: "Shave all of it, or leave all of it."
"I came to the Prophet [SAW] and I had hair. He said: 'This is bad,' and I thought he meant me, so I cut my hair then I came to him. He said to me: 'I didn't mean you, but this is better.'"
Chapter 6: Cutting the (Hair) - كتاب الزينة من السنن
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ دَاوُدَ الأَوْدِيِّ، عَنْ حُمَيْدِ بْنِ عَبْدِ الرَّحْمَنِ الْحِمْيَرِيِّ، قَالَ لَقِيتُ رَجُلاً صَحِبَ النَّبِيَّ صلى الله عليه وسلم كَمَا صَحِبَهُ أَبُو هُرَيْرَةَ أَرْبَعَ سِنِينَ قَالَ نَهَانَا رَسُولُ اللَّهِ صلى الله عليه وسلم أَنْ يَمْتَشِطَ أَحَدُنَا كُلَّ يَوْمٍ .
It was narrated that Humaid bin 'Abdur-Rahman Al-Himyari said:
"I met a man who accompanied the Prophet [SAW] as Abu Hurairah accompanied him for four years, who said: 'The Messenger of Allah [SAW] forbade us from combing our hair everyday.'"
Chapter 7: Combing the Hair Every Other Day - كتاب الزينة من السنن
أَخْبَرَنَا إِسْمَاعِيلُ بْنُ مَسْعُودٍ، قَالَ حَدَّثَنَا خَالِدُ بْنُ الْحَارِثِ، عَنْ كَهْمَسٍ، عَنْ عَبْدِ اللَّهِ بْنِ شَقِيقٍ، قَالَ كَانَ رَجُلٌ مِنْ أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم عَامِلاً بِمِصْرَ فَأَتَاهُ رَجُلٌ مِنْ أَصْحَابِهِ فَإِذَا هُوَ شَعِثُ الرَّأْسِ مُشْعَانٌّ قَالَ مَا لِي أَرَاكَ مُشْعَانًّا وَأَنْتَ أَمِيرٌ قَالَ كَانَ نَبِيُّ اللَّهِ صلى الله عليه وسلم يَنْهَانَا عَنِ الإِرْفَاهِ . قُلْنَا وَمَا الإِرْفَاهُ قَالَ التَّرَجُّلُ كُلَّ يَوْمٍ .
It was narrated that 'Abdullah bin Shaqiq said:
"One of the Companions of the Prophet [SAW] was a governor in Egypt, and one of his companions came to him and found him with unkempt, wild hair. He said: 'How come I see you with wild hair when you are a governor?' He said: 'The Prophet of Allah [SAW] forbade us from Al-Irfah,' and we said: 'What is Al-Irfah?' He said: 'To comb your hair every day.'"
"The Messenger of Allah [SAW] used to like to start in the right. He would accept with his right hand and give with his right hand, and he liked to start on the right in all his affairs."
Chapter 9: Letting the Hair Grow - كتاب الزينة من السنن
أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ عَمَّارٍ، قَالَ حَدَّثَنَا الْمُعَافَى، عَنْ إِسْرَائِيلَ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ، قَالَ مَا رَأَيْتُ أَحَدًا أَحْسَنَ فِي حُلَّةٍ حَمْرَاءَ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم وَجُمَّتُهُ تَضْرِبُ مَنْكِبَيْهِ .
It was narrated that Al-Bara' said:
"I have never seen anyone who looked more handsome in a red Hullah than the Messenger of Allah [SAW], with his long hair that came down to his shoulders."
"I have never seen any man more handsome in a red Hullah than the Messenger of Allah [SAW]." He said: "And I saw his long hair, coming almost to his shoulders."
"According to whose recitation do you want me to recite? Because I recited seventy-odd Surahs to the Messenger of Allah [SAW] when Zaid had two braids, and was playing with the other boys."
"Ibn Mas'ud addressed us and said: 'How do you want me to recite? According to the recitation of Zaid bin Thabit, when I learned seventy-odd Surahs from the mouth of the Messenger of Allah [SAW] while Zaid was with the other boys with two braids?'"