The Book of Commentary (Kitab Al-Tafsir)
Muslim :: Book 43 : Hadith 7184
Abdullah b. Mas'ud said in connection with the verse:" Those whom they call upon, themselves seek the means of access to their Lord," that that verse was revealed in connection with a party of Arabs who used to worship a group amnogst the jinn; the jinn embraced Islam but the people kept worshipping them without being conscious of it. Then this verse was revealed:" Those whom they call upon, themselves seek the means of access to their Lord."