Narrated `Abdullah:Allah's Messenger (ﷺ) said a sentence and I said another. He said, "Whoever dies while he is setting up rivals along with Allah (i.e. worshipping others along with Allah) shall be admitted into the (Hell) Fire." And I said the other: "Whoever dies while he is not setting up rivals along with Allah (i.e. worshipping none except Allah) shall be admitted into Paradise."
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا عَبْدُ الْوَاحِدِ، حَدَّثَنَا الأَعْمَشُ، عَنْ شَقِيقٍ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم كَلِمَةً وَقُلْتُ أُخْرَى " مَنْ مَاتَ يَجْعَلُ لِلَّهِ نِدًّا أُدْخِلَ النَّارَ ". وَقُلْتُ أُخْرَى مَنْ مَاتَ لاَ يَجْعَلُ لِلَّهِ نِدًّا أُدْخِلَ الْجَنَّةَ.
Bukhari
Oaths and Vows • Hadith 60