Musnad Ahmad 4137

It was narrated from 'Abdullah (رضي الله عنه) from the Prophet (ﷺ) that He recited (Soorat) an-Najm and prostrated in it, and those who were with him prostrated, except an old man who took a handful of pebbles or dust and raised it to his forehead and said: This is sufficient for me! ‘Abdullah said: And later on I saw him slain as a kafir.