Farwah b. Nawfal quoted his father as saying that the Prophet ﷺ said to Nawfal (his father):

Say , O infidels! and then sleep at its end, for it is a declaration of freedom from polytheism.

حَدَّثَنَا النُّفَيْلِيُّ، حَدَّثَنَا زُهَيْرٌ، حَدَّثَنَا أَبُو إِسْحَاقَ، عَنْ فَرْوَةَ بْنِ نَوْفَلٍ، عَنْ أَبِيهِ، أَنَّ النَّبِيَّ ﷺ قَالَ لِنَوْفَلٍ " اقْرَأْ { قُلْ يَا أَيُّهَا الْكَافِرُونَ } ثُمَّ نَمْ عَلَى خَاتِمَتِهَا فَإِنَّهَا بَرَاءَةٌ مِنَ الشِّرْكِ " .