Sunan Ibn Majah 2100
سنن ابن ماجه#2100SahihIt was narrated from Abdullah bin Buraidah that his father told that :the Messenger of Allah (ﷺ) said: "Whoever says: 'I have nothing to do with Islam,' if he is lying then he is as he said, and if he is telling the truth, his Islam will not be sound
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 ZaiIsnaad Hasan
In-book reference: 11:11