Hadith on Idolatry: Whoever dies supplicating to another god will enter the Fire

Abdullah ibn Mas’ud reported: The Prophet, peace be upon him, said a word and I said another. He said, “Whoever dies while calling upon other than Allah as a partner will enter Hellfire.” I said, “Whoever dies while not calling upon other than Allah as a partner will enter Paradise.”

[Sahih Bukhari, Book 60, Number 24]

عَنْ عَبْدِ اللَّهِ  قَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَلِمَةً وَقُلْتُ أُخْرَى قَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَنْ مَاتَ وَهْوَ يَدْعُو مِنْ دُونِ اللَّهِ نِدًّا دَخَلَ النَّارَ وَقُلْتُ أَنَا مَنْ مَاتَ وَهْوَ لَا يَدْعُو لِلَّهِ نِدًّا دَخَلَ الْجَنَّةَ

صحيح البخاري كِتَاب تَفْسِيرِ الْقُرْآنِ سُورَةُ الْبَقَرَةِ بَاب قَوْلِهِ وَمِنْ النَّاسِ مَنْ يَتَّخِذُ مِنْ دُونِ اللَّهِ أَنْدَادًا يُحِبُّونَهُمْ كَحُبِّ اللَّهِ