(2) باب لاَ تُقْبَلُ صَلاَةٌ بِغَيْرِ طُهُورٍ
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "The prayer of a person who does Hadath (passes urine, stool or wind) is not accepted till he performs the ablution." A person from Hadaramout asked Abu Huraira, "What is 'Hadath'?" Abu Huraira replied, " 'Hadath' means the passing of wind."
Reference: Sahih al-Bukhari 135
In-book reference: Book 4, Hadith 1
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 4, Hadith 137