Musnad Ahmad 1028, 1029
It was narrated that ‘Ali (رضي الله عنه) said:
I was a man who emitted a great deal of madhi, so I asked the Prophet (ﷺ) and he said: “If you see madhi then do wudoo’ and wash your private part, and if you see water gushing then do ghusl.` I [the narrator] mentioned that to Sufyan and he said: I heard that from Rukain.


Mu`awiyah and ibn Abi Bukair told us: Za`idah told us: ar-Rukain bin ar-Rabee bin ‘Ameelah al-Fazari told us... And he mentioned a similar report, and they said: water gushing. And Ibn Abu Bukair told us: Za`idah told us, and he also said, gushing.
حَدَّثَنَا عَبْدُ الرَّحْمَنِ، حَدَّثَنَا زَائِدَةُ، عَنْ الرُّكَيْنِ بْنِ الرَّبِيعِ، عَنْ حُصَيْنِ بْنِ قَبِيصَةَ، عَنْ عَلِيٍّ، رَضِيَ اللَّهُ عَنْهُ قَالَ كُنْتُ رَجُلًا مَذَّاءً فَسَأَلْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ إِذَا رَأَيْتَ الْمَذْيَ فَتَوَضَّأْ وَاغْسِلْ ذَكَرَكَ وَإِذَا رَأَيْتَ فَضْخَ الْمَاءِ فَاغْتَسِلْ فَذَكَرْتُهُ لِسُفْيَانَ فَقَالَ قَدْ سَمِعْتُهُ مِنْ رُكَيْنٍ.
حَدَّثَنَا مُعَاوِيَةُ وَابْنُ أَبِي بُكَيْرٍ قَالَا حَدَّثَنَا زَائِدَةُ حَدَّثَنَا الرُّكَيْنُ بْنُ الرَّبِيعِ بْنِ عَمِيلَةَ الْفَزَارِيُّ فَذَكَرَ مِثْلَهُ وَقَالَا فَضْخَ الْمَاءِ وَحَدَّثَنَا ابْنُ أَبِي بُكَيْرٍ حَدَّثَنَا زَائِدَةُ وَقَالَ فَضْخَ أَيْضًا‏.‏