Narrated 'Abdullah:

While Allah's Apostle was prostrating (as stated below).

وَبِإِسْنَادِهِ قَالَ
" لاَ يَبُولَنَّ أَحَدُكُمْ فِي الْمَاءِ الدَّائِمِ الَّذِي لاَ يَجْرِي، ثُمَّ يَغْتَسِلُ فِيهِ ".