Hadith 1111:8
'Affan narrated to us, Hammad narrated to us, 'Abd al-Rahman ibn Abi Rafi' informed us, from his paternal aunt Salma, from Abu Rafi': That the Messenger of Allah (peace and blessings of Allah be upon him) went around to his wives in one day, and he would perform ghusl (ritual bath) at this one's [house] and at that one's [house]. It was said: "O Messenger of Allah, if you were to make it one ghusl?" He said: "This is purer, better, and cleaner."
حدثنا عفان، حدثنا حماد، أخبرنا عبد الرحمن بن أبي رافع، عن عمته سلمى، عن أبي رافع: أن رسول الله صلى الله عليه وسلم طاف على نسائه في يوم، فجعل يغتسل عند هذه وعند هذه، فقيل: يا رسول الله، لو جعلته غسلا واحدا قال: " هذا أزكى وأطيب وأطهر "