Sunan Ibn Majah 507
It was narrated from Ibn 'Abbas that:
He came to Ubayy bin Ka'b accompanied by 'Umar. Ubayy came out to them and said: "I noticed some prostatic fluid, so I washed my penis and performed ablution. 'Umar said: "Is that sufficient?" He said: "Yes." He ('Umar) asked: "Did you hear that from the messenger of Allah?" He said: "Yes."
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ بِشْرٍ، حَدَّثَنَا مِسْعَرٌ، عَنْ مُصْعَبِ بْنِ شَيْبَةَ، عَنْ أَبِي حَبِيبِ بْنِ يَعْلَى بْنِ مُنْيَةَ، عَنِ ابْنِ عَبَّاسٍ، أَنَّهُ أَتَى أُبَىَّ بْنَ كَعْبٍ وَمَعَهُ عُمَرُ فَخَرَجَ عَلَيْهِمَا فَقَالَ إِنِّي وَجَدْتُ مَذْيًا فَغَسَلْتُ ذَكَرِي وَتَوَضَّأْتُ . فَقَالَ عُمَرُ أَوَ يُجْزِئُ ذَلِكَ قَالَ نَعَمْ . قَالَ أَسَمِعْتَهُ مِنْ رَسُولِ اللَّهِ ﷺ قَالَ نَعَمْ .