The Book of Purification
1/126. Chapter:
Mentioning When Ghusl (A Purifying Bath) Is Obligatory And When It Is Not - The Ghusl Of The Disbeliever when He Accepts Islam
Sunan an-Nasai
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الأَغَرِّ، - وَهُوَ ابْنُ الصَّبَّاحِ - عَنْ خَلِيفَةَ بْنِ حُصَيْنٍ، عَنْ قَيْسِ بْنِ عَاصِمٍ، أَنَّهُ أَسْلَمَ فَأَمَرَهُ النَّبِيُّ صلى الله عليه وسلم أَنْ يَغْتَسِلَ بِمَاءٍ وَسِدْرٍ .
It was narrated from Qais bin 'Asim that he accepted Islam, and the Prophet commanded him to perform Ghusl with water and lotus leaves.
Reference : Sunan an-Nasa'i 188In-book reference : Book 1, Hadith 189English translation : Vol. 1, Book 1, Hadith 188