Narrated Haritha bin Wahb:

I heard the Prophet 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)." Haritha said that he heard the Prophet saying that his Lake-Fount would be as large as the distance between Sana' and Medina. Al-Mustaurid said to Haritha, "Didn't you hear him talking about the vessels?" He said, "No." Al-Mustaurid said, "The vessels are seen in it as (numberless as) the stars."

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا حَرَمِيُّ بْنُ عُمَارَةَ، حَدَّثَنَا شُعْبَةُ، عَنْ مَعْبَدِ بْنِ خَالِدٍ، أَنَّهُ سَمِعَ حَارِثَةَ بْنَ وَهْبٍ، يَقُولُ سَمِعْتُ النَّبِيَّ ﷺ وَذَكَرَ الْحَوْضَ فَقَالَ
" كَمَا بَيْنَ الْمَدِينَةِ وَصَنْعَاءَ ".