135. Narrated Abu Hurairah: Allah’s Messenger, peace be upon him, said, “The Salat (prayer) of a person who does Hadath (passes urine, stool or wind) is not accepted till he performs (repeats) the ablution.”
A person from Hadaramout asked Abu Hurairah, “What is Hadath?” Abu Hurairah replied, “Hadath means the passing of wind from the anus.”
137. Narrated ‘Abbad bin Tamim: My uncle asked Allah’s Messenger, peace be upon him, about a person who imagined to have passed wind during Salat (prayer). Allah’s Messenger, peace be upon him, replied: “He should not leave his Salat unless he hears sound or smells something.”