Hadith 3:239
Qais b. ‘Asim said that when he accepted Islam the Prophet commanded him to bathe with water and lote-tree leaves. Tirmidhi, Abu Dawud and Nasa’i transmitted it.
وَعَن قيس بن عَاصِم: أَنَّهُ أَسْلَمَ فَأَمَرَهُ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنْ يَغْتَسِلَ بِمَاءٍ وَسِدْرٍ. رَوَاهُ التِّرْمِذِيُّ وَأَبُو دَاوُدَ وَالنَّسَائِيُّ
Original Reference: Mishkat al-Masabih 543