حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ سَمِعَهُ وَرَجُلٌ، يَسْأَلُهُ فَقَالَ إِنِّي لأَجِدُ الْبَلَلَ وَأَنَا أُصَلِّي، أَفَأَنْصَرِفُ فَقَالَ لَهُ سَعِيدٌ لَوْ سَالَ عَلَى فَخِذِي مَا انْصَرَفْتُ حَتَّى أَقْضِيَ صَلاَتِي ‏.‏

Yahya related to me from Malik from Yahya ibn Said that he waslistening to Said ibn al-Musayyab and a man questioned him saying, "Idiscover a liquid when I am praying. Should I leave?" Saidibn al-Musayyab said to him, "Even if it were to flow on my leg Iwould not leave until I had finished the prayer." Translation Not Available

Book Ref: Muwatta Imam Malik Book 2 Hadith 88
Web Ref:  Muwatta Imam Malik Book 2 Hadith 58