Sunan Ibn Majah 297
سنن ابن ماجه#297Da'ifIt was narrated that 'Ali said:"The Messenger of Allah said: 'The screen between the Jinn and the nakedness of the sons of Adam is that when a person enters the Kanif, he should say: Bismillah (in the name of Allah)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Zubair Ali ZaiDaif
In-book reference: 1:31