THE STORY OF ABU MUSLIM KHOULANI (Rahimahullah)
... He had a slave girl who used to poison his food. He would eat it and not get affected by the poison. Many days passed this way.
She then told him, “I am poisoning your food for so many days but why is it not affecting you in any way?”
Abu Muslim asked her, “Why do you wish to poison me?”
She replied, “You are growing old and I wish to free myself from you.”
He replied, “The reason why the poison had no effect was, because I recite Bismillah on whatever I eat or drink.”
He then freed the slave girl so that she could marry whoever she wanted to. (Qalyoobi page53)