It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Take a ritual bath (ghusl) on Friday, for whoever takes a ritual bath on Friday, it is an expiation for him for (the sins) between one Friday and the next, and three days more."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7709