The sincerity of declaring monotheism in Islam
Ṣifāt al-Shīʿa|Volume 1|Book 1|Chapter 7
حَدَّثَنَا أَبِي رَحِمَهُ اَللَّهُ قَالَ حَدَّثَنَا سَعْدُ بْنُ عَبْدِ اَللَّهِ عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ وَ اَلْحَسَنِ بْنِ عَلِيٍّ اَلْكُوفِيِّ وَ إِبْرَاهِيمَ بْنِ هَاشِمٍ كُلُّهُمْ عَنِ اَلْحُسَيْنِ بْنِ يُوسُفَ عَنْ سُلَيْمَانَ بْنِ عَمْرٍو عَنْ مُهَاجِرِ بْنِ اَلْحُسَيْنِ عَنْ زَيْدِ بْنِ أَرْقَمَ عَنِ اَلنَّبِيِّ ص قَالَ : مَنْ قَالَلاَ إِلَهَ إِلاَّ اَللَّهُمُخْلِصاً دَخَلَ اَلْجَنَّةَ وَ إِخْلاَصُهُ بِهَا أَنْ يَحْجُزَهُلاَ إِلَهَ إِلاَّ اَللَّهُعَمَّا حَرَّمَ اَللَّهُ.
My father, Allah may have mercy upon him, narrated to us from Sa’d bin Abdullah from Ahmed bin Mohammed, al-Hasan bin Ali al-Kufi, and al-Hussein bin Saif from Sulaiman bin Amr from Muhajir Abu al-Hasan from Zaid bin Arqam that the Prophet صلى الله عليه وعلى آله وسلم said: He who says ‘La ilaha illa عليه السلامllah’ –there is no god but Allah- sincerely will be in Paradise. Sincerity, here, means that this saying should prevent him from violating the things that Allah forbids.