Anas reported God's Messenger as saying, “If anyone forgets a stated prayer or oversleeps, expiation is made by observing it when he remembers it.” A version has “That is the only expiation for it.” (Bukhari and Muslim.)
Hadith Referenceمشكوة المصابيح / كتاب الصلاة / 603
Hadith Gradingالألبانی:مُتَّفَقٌ عَلَيْهِ | زبیر علی زئی:متفق عليه
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «متفق عليه، رواه البخاري (597) و مسلم (315/ 684)»