(53) باب فِي الْحَوْضِ
Narrated Haritha bin Wahb:
I heard the Prophet (ﷺ) mentioning the Lake-Fount (Al-Kauthar), saying, "(The width of the Lake-Fount) is equal to the distance between Medina and Sana' (capital of Yemen)."
Reference: Sahih al-Bukhari 6591
In-book reference: Book 81, Hadith 179
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 8, Book 76, Hadith 591