Hadith 1228:8
Yazid narrated to us, Hammad ibn Salamah informed us, from Abd al-Rahman, from his paternal aunt, from Abu Rafi, that the Messenger of Allah (peace and blessings of Allah be upon him) went around to his wives in one night and performed ghusl (a ritual bath) with each one of them. I said: "O Messenger of Allah, would it not be better if you performed one ghusl?" He replied: "This is purer and better."
حدثنا يزيد، أخبرنا حماد بن سلمة، عن عبد الرحمن، عن عمته، عن أبي رافع، أن رسول الله صلى الله عليه وسلم: طاف على نسائه في ليلة فاغتسل عند كل امرأة منهن غسلا، فقلت: يا رسول الله، لو اغتسلت غسلا واحدا؟، فقال: " هذا أطهر وأطيب "