Hadith: Ten practices are part of the Fitrah: Trimming the mustache, letting the beard grow, using the tooth-stick, rinsing the nose, trimming the nails, washing the finger joints, plucking the armpit hair, shaving the pubic hair, and washing the private parts with water

عن عائشة رضي الله عنها مرفوعاً: «عَشْرٌ من الفِطْرة: قَصُّ الشَارب، وإعْفَاء اللِّحْية، والسِّواك، وَاسْتِنْشَاقُ الماء، وقص الأظْفَار، وغَسْل البَرَاجِم، ونَتْف الإبْط، وحلق العَانة، وانْتِقَاصُ الماء» قال الراوي: ونَسِيْتُ العاشرة إلا أن تكون المَضْمَضَة. قال وكِيع - وهو أحد رواته - انْتِقَاص الماء: يعني الاسْتِنْجَاء.
[صحيح] - [رواه مسلم]

‘Ā’ishah (may Allah be pleased with her) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Ten practices are part of the Fitrah: Trimming the mustache, letting the beard grow, using the toothstick (tooth-stick), rinsing the nose, trimming the nails, washing the finger joints, plucking the armpit hairs, shaving the pubic hair, and washing the private parts with water (after answering the call of nature)." One of the narrators said: "I have forgotten the tenth; except if it was rinsing the mouth."
Sahih/Authentic. - [Muslim]

Explanation

In this narration, ‘Ā’ishah (may Allah be pleased with her) informs us that the Prophet (may Allah's peace and blessings be upon him) said that there are ten practices that are part of "Fitrah" or sound human nature. "Fitrah" is the natural disposition upon which Allah, the Almighty, created people. What is intended is the sound "Fitrah" because the "Fitrah" of some people deviates from soundness as a result of the way they are raised. The Prophet (may Allah's peace and blessings be upon him) said: "c2">“Every newborn is born with Fitrah, and then his parents either turn him into a Jew or a Christian or a Zoroastrian.” The first act of Fitrah is to trim the mustache or to shave it to the point where the upper lip becomes visible, for the sake of hygiene. When the mustache is too long it comes into contact with the food and drink that the person consumes. An overgrown mustache is an ugly and abhorrent sight for many people. A Muslim man should regularly trim or clip his mustache and not let it grow for more than forty days. Anas (may Allah be pleased with him) reported: A time limit was set for us regarding trimming the mustache, clipping the nails and plucking the pubic hair; that we do not leave that for more than forty nights. The second act of Fitrah is letting the beard grow. The beard is the hair that grows on the chin and jawbones. "c2">“Letting it grow” meanings not to shave or shorten it at all. The word "i‘fā’" which is used in the Hadīth in relation to the beard originally means making something plentiful and large. The derivative "‘afaw" is used in the Qur'an to mean increase in the verse: {until they increased and prospered} [Sūrat al-A‘rāf: 95]. There are many Hadīths where the Prophet (may Allah's peace and blessings be upon him) ordered the Muslims to grow their beards. He used three different words to command his followers to let their beards grow: "waffiru", "arkhu", and "a‘foo". All three imperatives indicate the command to keep it grown and refrain from taking from it. Accordingly it is impermissible for the Muslim man to shave his beard under any circumstances. Shaving the beard is against the practice of the Prophet, disobedience to his command, and imitation of the non-believers. The third act of Fitrah is to use the tooth-stick. The Prophet (may Allah's peace and blessings be upon him) said about it: "It cleanses the mouth and pleases the Lord." It is recommended to use it at all times, and its use is especially emphasized before ablution, before prayer, after waking up from sleep, when someone’s breath becomes foul, and when the teeth become yellow. The fourth act of Fitrah is rinsing the nose, which literally means sniffing the water (i.e. and then blowing it out). It cleans the nose by removing from inside it what may cause harm. This should be done both in wudu and outside of wudu. Any time a person feels that he needs to clean his nose, he should rinse it with water (by sniffing water in and blowing it out). The frequency of this cleansing may differ from person to person because some may only need to do it in ablution while others may need to do it more frequently. The fifth act of Fitrah is clipping the nails, both finger and toe nails. They should not be left without clipping for more than forty days, based on the narration of Anas (may Allah be pleased with him) mentioned above. And in a narration by Abu Dawūd: "The Messenger of Allah timed for us the shaving the pubes and clipping the nails." The sixth act of Fitrah is washing the finger joints on the outside and inside of the hand. Dirt tends to accumulate in them because they are creased and wrinkled and hence water may not clean them thoroughly when the hands are washed superficially. If the joints of one hand are rubbed by the other hand, water will reach into the areas and clean them thoroughly. Similar to the finger joints is any place on the body where dirt tends to accumulate with or without sweat, such as the ear canal, the inner thighs, and anywhere else that water may not thoroughly reach. The seventh act is plucking armpit hair. The armpits are an area where sweat and dirt gather and cause a stench. They should not be left unshaven for more than forty days, based on the aforementioned narration of Anas (may Allah be pleased with him). It is better to pluck the armpit hair rather than shave it if one is able to do so because that removes the whole hair and weakens the roots and therefore eventually hinders hair growth in that area, which is recommended in the Shariah. If plucking is overly difficult it is acceptable to shave it or to use depilatory (hair removing) creams because the objective is to clean the area which is achieved by shaving or using such creams. The eighth act of Fitrah is shaving the pubic hair, which is the coarse hair that grows around the frontal genitals of both men and women. It is part of sound and wholesome human nature to remove this hair, whether by shaving, plucking, trimming, or using modern products. The objective is to keep that area clean using any available means. It is important not to let the pubic hair grow for more than forty days, based on the above mentioned narration of Anas. The ninth act of Fitrah mentioned in the Hadīth is "intiqās al-mā’", which was interpreted to mean "istinjā’" or washing one's genitals with water after using the lavatory. This interpretation is corroborated by the narration of Abu Dawūd and Ibn Mājah where ‘Ammar ibn Yāsir (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "From the acts of Fitrah are: rinsing the mouth, sniffing water into the nose … and intidāh (i.e. sprinkling water over the genitals)." Istinjā’ is defined as removing any residue of what comes out of the front and back passages of human excretion, (urine and stool, etc.) with a pure substance such as water, stone, cloth, tissue paper, and similar things by which the filth can be removed. Istinjā’ is mandatory before one prays because removal of impurities is a condition for the validity of prayer. The narrator was doubtful what the tenth act of Fitrah was, and said: "...and I have forgotten the tenth, except if it was rinsing the mouth." This is doubt about what he heard from the narrator who preceded him in the chain of narration. The mouth and nose both receive much pollutants and thus it is part of sound nature to clean them regularly. In brief, all of these acts clean, cleanse and perfect the outside of a person's body, and keep him safe from harmful elements and bad hygiene.