The Messenger of Allah ﷺ said, "The prayer," and in another narration, "The five daily prayers, and one Friday prayer to the next, are an expiation for whatever sins occur between them, as long as major sins are avoided."In another narration, he added, "And one Ramadan to the next are expiations as well."
أن رسول الله ﷺ، قال: الصلاة- وفي رواية: الصلوات الخمس، والجمعة إلى الجمعة كفارة لما بينهن ما لم تغش الكبائر. وزاد في رواية: ورمضان إلى رمضان مكفرات.
Muslim narrated it in "Purification" (233) through multiple routes from Ismail bin Jafar, "Ala bin Abdul-Rahman, the freedman of Hurqah, informed me, from his father, from Abu Hurairah," and he mentioned it.