The Messenger of Allah ﷺ said, "Whoever applies kohl, let him do so an odd number of times. Whoever does so has done well, and whoever does not, there is no harm upon him.Whoever cleans himself with stones after relieving himself, let him use an odd number. Whoever does so has done well, and whoever does not, there is no harm.Whoever eats and picks his teeth, let him spit out what he removes, and whoever works it loose with his tongue, let him swallow it. Whoever does so has done well, and whoever does not, there is no harm.Whoever goes to relieve himself, let him conceal himself. If he finds nothing else, let him gather a mound of sand and turn his back to it, for Satan toys with the backsides of the children of Adam. Whoever does so has done well, and whoever does not, there is no harm."
حدثنا سريج قال حدثنا عيسى بن يونس عن ثور عن الحصين كذا قال عن أبي سعد الخير وكان من أصحاب عمر
قال رسول الله ﷺ من اكتحل فليوتر ومن فعل فقد أحسن ومن لا فلا حرج عليه ومن استجمر فليوتر ومن فعل فقد أحسن ومن لا فلا حرج ومن أكل فما تخلل فليلفظ ومن لاك بلسانه فليبتلع من فعل فقد أحسن ومن لا فلا حرج ومن أتى الغائط فليستتر فإن لم يجد إلا أن يجمع كثيبا فليستدبره فإن الشيطان يلعب بمقاعد بني آدم من فعل فقد أحسن ومن لا فلا حرج
Its isnad is daif, because of Abu Saad al-Khayr al-Khuzai (also said to be al-Himyari), who is unknown in status, as Abu Hatim said (al-Jarh 9/378), and likewise Ibn Hajar and others said the same. It also contains Husayn, whom Ibn Hajar deemed unknown in al-Taqrib, though Ibn Hibban mentioned him in al-Thiqat.The hadith itself is sahih. Abu Dawud reported it with this wording, 1/9, number 35, in the Book of Purification, chapter on covering oneself while relieving oneself. Bukhari reported something similar, 1/52, in the Book of Wudu, chapter on wiping with stones an odd number of times. Muslim also reported it, 1/212, number 237m, in the Book of Purification, chapter on sniffing water up the nose an odd number of times. And Ibn Majah reported it, 1/121, number 337, in the Book of Purification, chapter on seeking a suitable place for relieving oneself and urinating.