أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنْ إِسْحَاقَ بْنِ عَبْدِ اللَّهِ بْنِ أَبِي طَلْحَةَ، عَنْ حُمَيْدَةَ بِنْتِ عُبَيْدِ بْنِ رِفَاعَةَ، عَنْ كَبْشَةَ بِنْتِ كَعْبِ بْنِ مَالِكٍ، أَنَّ أَبَا قَتَادَةَ، دَخَلَ عَلَيْهَا ثُمَّ ذَكَرَ كَلِمَةً مَعْنَاهَا فَسَكَبْتُ لَهُ وَضُوءًا فَجَاءَتْ هِرَّةٌ فَشَرِبَتْ مِنْهُ فَأَصْغَى لَهَا الإِنَاءَ حَتَّى شَرِبَتْ قَالَتْ كَبْشَةُ فَرَآنِي أَنْظُرُ إِلَيْهِ فَقَالَ أَتَعْجَبِينَ يَا ابْنَةَ أَخِي قُلْتُ نَعَمْ ‏.‏ قَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ إِنَّهَا لَيْسَتْ بِنَجَسٍ إِنَّمَا هِيَ مِنَ الطَّوَّافِينَ عَلَيْكُمْ وَالطَّوَّافَاتِ ‏"‏ ‏.‏

It was narrated from Kabshah bint Ka'ab bin Malik that Abu Qatadah entered upon her, then she narrated the following: "I poured some water for him for Wudu', and a cat came and drank from it, so he tilted the vessel for it to drink." Kabshah said: "He saw me looking at him and said: 'Are you surprised, O daughter of my brother?' I said: 'Yes.' He said: 'The Messenger of Allah (PBUH) said: 'They are not impure, rather they are among the males and females (animals) who go around among you." Translation Not Available

Book Ref: Sunan An Nisai Book 2 Hadith 340
Web Ref:  Sunan An Nisai Vol 1 Book 2 Hadith 341