Sahih Bukhari Volume 2, Book 13, Hadith Number 26

Narated By Yahya bin Said : I asked ‘Amra about taking a bath on Fridays. She replied, “‘Aisha said, ‘The people used to work (for their livelihood) and whenever they went for the Jumua prayer, they used to go to the mosque in the same shape as they had been in work. So they were asked to take a bath on Friday.’ “