مُوَطَّأُ مَالِكٍ
Muwatta Malik 89
Purity
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنِ الصَّلْتِ بْنِ زُيَيْدٍ، أَنَّهُ قَالَ سَأَلْتُ سُلَيْمَانَ بْنَ يَسَارٍ عَنِ الْبَلَلِ، أَجِدُهُ فَقَالَ انْضَحْ مَا تَحْتَ ثَوْبِكَ بِالْمَاءِ وَالْهَ عَنْهُ .
Yahya related to me from Malik that as-Salt ibn Zuyayd said, "I asked Sulayman ibn Yasar about a liquid I discovered. He said, 'Wash what is under your garments with water and forget about it.' "
Arabic/English book reference: Book 2, Hadith 59