Dawud b. Salih b. Dinar quoted his mother as saying that her mistress sent her to ‘A'isha with some hari a. She said that she found her praying and that she signed to her to lay it down. A cat came and ate some of it, but when ‘A'isha finished praying she ate from the place where the cat had eaten, stating that God’s messenger had said, “It is not unclean; it is one of those who go round among you adding that she had seen God’s messenger using water it had left to perform his ablution. Abu Dawud transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَن دَاوُد بن صَالح بن دِينَار التمار عَنْ أُمِّهِ أَنَّ مَوْلَاتَهَا أَرْسَلَتْهَا بِهَرِيسَةٍ إِلَى عَائِشَةَ قَالَتْ: فَوَجَدْتُهَا تُصَلِّي فَأَشَارَتْ إِلَيَّ أَنْ ضَعِيهَا فَجَاءَتْ هِرَّةٌ فَأَكَلَتْ مِنْهَا فَلَمَّا انْصَرَفَتْ عَائِشَةُ مِنْ صَلَاتِهَا أَكَلَتْ مِنْ حَيْثُ أَكَلَتِ الْهِرَّةُ فَقَالَتْ إِنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «إِنَّهَا لَيست بِنَجس إِنَّمَا هِيَ من الطوافين عَلَيْكُم» . وَقَدْ رَأَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يتَوَضَّأ بفضلها. رَوَاهُ أَبُو دَاوُد
sunnah.com