Sunan Ibn Majah
Hadith #598
Abu Ayyub Al-Ansari narrated that:The Prophet said: ""The five daily prayers, from one Friday to the next, and fulfilling the trust are all expiation for whatever (sins) come between them."" I said: ""What is fulfilling the trust?"" He said: Having a bath to cleanse oneself from sexual impurity, for under every hair there is the state of sexual impurity