Aisha reported: The Messenger of Allah, peace and blessings be upon him, said, “Ten acts are part of natural instinct: trimming the moustache, letting the beard grow, using the toothstick, sniffing water into the nose, clipping the nails, washing the knuckles, removing hair from the underarms, shaving the pubic hair, and cleaning the private parts with water.” Mus’ab said, “I forgot the tenth, except that it might be rinsing the mouth.”
Source: Ṣaḥīḥ Muslim 261
Grade: Sahih (authentic) according to Muslim
عَنْ عَائِشَةَ قَالَتْ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَشْرٌ مِنْ الْفِطْرَةِ قَصُّ الشَّارِبِ وَإِعْفَاءُ اللِّحْيَةِ وَالسِّوَاكُ وَاسْتِنْشَاقُ الْمَاءِ وَقَصُّ الْأَظْفَارِ وَغَسْلُ الْبَرَاجِمِ وَنَتْفُ الْإِبِطِ وَحَلْقُ الْعَانَةِ وَانْتِقَاصُ الْمَاءِ قَالَ مُصْعَبٌ وَنَسِيتُ الْعَاشِرَةَ إِلَّا أَنْ تَكُونَ الْمَضْمَضَةَ
261 صحيح مسلم كتاب الطهارة باب خصال الفطرة