Al-Kāfi - Volume 2 > The Excellence of the Holy Quran
Hadith #23

23ـ عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ سَهْلِ بْنِ زِيَادٍ عَنْ إِسْمَاعِيلَ بْنِ مِهْرَانَ عَنْ صَفْوَانَ بْنِ يَحْيَى عَنْ عَبْدِ الله بْنِ سِنَانٍ عَنْ أَبِي عَبْدِ الله (عَلَيهِ السَّلام) أَنَّهُ قَالَ مَنْ قَرَأَ إِذَا أَوَى إِلَى فِرَاشِهِ قُلْ يَا أَيُّهَا الْكَافِرُونَ وَقُلْ هُوَ الله أَحَدٌ كَتَبَ الله عَزَّ وَجَلَّ لَهُ بَرَاءَةً مِنَ الشِّرْكِ.

23. A number of our people have narrated from Sahl ibn Ziyad from Isma’il ibn Mehran from Safwan ibn Yahya from ‘Abd Allah ibn Sinan from abu ‘Abd Allah (a.s.) who has said the following: “Whoever at the time of going to bed reads Chapter 109 of the Holy Quran, Allah, the Most Majestic, the Most Holy, will write down for him immunity from polytheism.”