'A'isha reported that Allah's Messenger (ﷺ) went out one norning wearing a striped cloak of the black camel's hair that there came Hasan b. 'Ali. He wrapped hitn under it, then came Husain and he wrapped him under it along with the other one (Hasan). Then came Fatima and he took her under it, then came 'Ali and he also took him under it and then said: Allah only desires to take away any uncleanliness from you, O people of the household, and purify you (thorough purifying)
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَمُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ، - وَاللَّفْظُ لأَبِي بَكْرٍ - قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ بِشْرٍ، عَنْ زَكَرِيَّاءَ، عَنْ مُصْعَبِ بْنِ شَيْبَةَ، عَنْ صَفِيَّةَ بِنْتِ شَيْبَةَ، قَالَتْ قَالَتْ عَائِشَةُ خَرَجَ النَّبِيُّ صلى الله عليه وسلم غَدَاةً وَعَلَيْهِ مِرْطٌ مُرَحَّلٌ مِنْ شَعْرٍ أَسْوَدَ فَجَاءَ الْحَسَنُ بْنُ عَلِيٍّ فَأَدْخَلَهُ ثُمَّ جَاءَ الْحُسَيْنُ فَدَخَلَ مَعَهُ ثُمَّ جَاءَتْ فَاطِمَةُ فَأَدْخَلَهَا ثُمَّ جَاءَ عَلِيٌّ فَأَدْخَلَهُ ثُمَّ قَالَ { إِنَّمَا يُرِيدُ اللَّهُ لِيُذْهِبَ عَنْكُمُ الرِّجْسَ أَهْلَ الْبَيْتِ وَيُطَهِّرَكُمْ تَطْهِيرًا}
sunnah.com