What a Person Should Say When They Lie Down to Sleep
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 64
وَ رَوَى عَبْدُ اَللَّهِ بْنُ سِنَانٍ عَنْ أَبِي عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ قَالَ لَهُ: «اِقْرَأْ «قُلْ هُوَ اَللّٰهُ أَحَدٌ» وَ «قُلْ يٰا أَيُّهَا اَلْكٰافِرُونَ» عِنْدَ مَنَامِكَ فَإِنَّهَا بَرَاءَةٌ مِنَ اَلشِّرْكِ وَ «قُلْ هُوَ اَللّٰهُ أَحَدٌ» نِسْبَةُ اَلرَّبِّ عَزَّ وَ جَلَّ.
Abdullah ibn Sinan reports from Imam Jafar ibn Muhammad Al-Sadiq عليه السلام who said: "Recite 'Qul Huwa Allahu Ahad' (Surah Al-Ikhlas) and ‘Qul ya-ayyuhal kaafirun’ (Surah al-Kafirun) before you sleep, for they are a declaration of freedom from shirk (associating partners with Allah سبحانه وتعالى), and 'Qul Huwa Allahu Ahad' (Surah Al-Ikhlas) affirms the nature of the Lord عز وجل, Mighty and Majestic."
- Ṣaḥīḥ al-Faqīh