(13) باب حُجَّةِ مَنْ قَالَ لاَ يَجْهَرُ بِالْبَسْمَلَةِ
Anas reported:
I observed prayer along with the Messenger of Allah (ﷺ) and with Abu Bakr, Umar and Uthman (may Allah be pleased with all of them), but I never heard any one of them reciting Bismillah-ir-Rahman-ir-Rahim loudly.
Reference: Sahih Muslim 399 a
In-book reference: Book 4, Hadith 52
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 786