Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The five prayers and Friday (prayer) to the next Friday are an expiation for all the sins committed in between them, as long as major sins are not committed, and (Friday) also becomes an expiation for the sins committed in the next three days."