Whenever the Prophet ﷺ went to his bed each night, he would cup his hands together, breathe into them, and recite into them "Say, He is Allah, the One" [Ikhlas 112:1], "Say, I seek refuge with the Lord of the daybreak" [Falaq 113:1], and "Say, I seek refuge with the Lord of mankind" [Nas 114:1]. Then he would wipe with them whatever he could reach of his body, beginning with his head and his face and the front of his body. He did this three times.
أن النبي ﷺ كان إذا أوى إلى فراشه كل ليلة جمع كفيه، ثم نفث فيهما، فقرأ فيهما، {قل هو الله أحد} [سورة الإخلاص: ١] {قل أعوذ برب الفلق} [سورة الفلق: ١] {قل أعوذ برب الناس} [سورة الناس: ١]، ثم يمسح بهما ما استطاع من جسده، يبدأ بهما على رأسه ووجهه وما أقبل من جسده يفعل ذلك ثلاث مرات.
Bukhari narrated it in the Virtues of the Quran (5017) from Qutayba bin Saeed, who said, Mufaddal narrated to us, from Aqeel, from Ibn Shihab, from Urwa, from Ayesha, and he related it.In this hadith, the Messenger of Allah ﷺ used to do that three times, while in the previous narration no specific number was mentioned. So whoever does that three times has done well, and whoever does it fewer times than that, there is no blame on him.