The Proof Of Those Who Say That The Basmalah Should Not Be Recited Aloud Sahih Muslim 399 a
Translation
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.