Hadith 2:160
And Muslim added:
"They would not recite Bismillahir-Rahmanir-Rahim, neither in the beginning of the recitation nor at the end of it."
زَادَ مُسْلِمٌ: { لَا يَذْكُرُونَ : (بِسْمِ اَللَّهِ اَلرَّحْمَنِ اَلرَّحِيمِ ) فِي أَوَّلِ قِرَاءَةٍ وَلَا فِي آخِرِهَا }