Hisn al-Muslim
Book 1: Fortress of the Muslim (Hisn al-Muslim)
حصن المسلم
268 hadith in this book
Chapter 5 Before undressing
ما يقول إذا وضع الثوب
BismillāhiIn the Name of Allah.Reference:At-Tirmidhi 2/505, among others. See 'Irwa'ul Ghalil no. 49 and
Sahihul-Jami' 3/203
بِسْمِ الله
Hadith text, translations and grading are courtesy of Sunnah.com.