صحيح البخاري
Sahih Bukhari
كتاب الاستئذان
The Book of Asking Permission
باب السلام اسم من أسماء الله تعالى:
Chapter. As-Salam is one of the Names of Allah: (Allah’s Statement): "When you are greeted with a greeting, greet in return with what is better than it, or (at least) return it equally..." (V.4:86)