Sunan Abu Dawud
40
Hasan+2

Narrated Aisha, Ummul Mu'minin: The Messenger of Allah (ﷺ) said: When any of you goes to relieve himself, he should take with him three stones to cleans himself, for they will be enough for him

HasanAl-Albani
HasanMuhammad Muhyi Al-Din Abdul Hamid