Abdullah b. Umar is reported to have said that The Messenger of Allah (may peace be up on him) was standing on the pulpit when he said this:
He who comes for Jumu'a he should take a bath. (JA)
Reference (JA): Sahih Muslim 844 b (JA)
In-book reference (JA): Book 7, Hadith 2 (JA)
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1833 (JA)