Anas bin Malik reported,

The Messenger of Allah ﷺ said, "I have been granted al-Kawthar, and there it was, a river flowing like this upon the surface of the earth. Its banks were domes of pearl, not hollowed out. I struck my hand into its soil, and behold, it was strongly fragrant musk, and its pebbles were pearls."

Ahmad 12542

Sahih

حدثنا عبد الصمد حدثنا حماد عن ثابت

عن أنس قال

قال رسول الله ﷺ أعطيت الكوثر فإذا هو نهر يجري كذا على وجه الأرض حافتاه قباب اللؤلؤ ليس مشفوفا فضربت بيدي إلى تربته فإذا مسكة ذفرة وإذا حصاه اللؤلؤ

أحمد 12542صحيح
Contents
Reference
Commentary
Ayat
Collection
Musnad Ahmad
Book
Anas bin Malik
Numbering
Darussalam 12542
Ahmad 12542