Observing Prayer Early in the Period - Section 1 Mishkat al-Masabih 603
Arabic hadith text
وَعَنْ أَنَسٍ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ نَسِيَ صَلَاةً أَوْ نَامَ عَنْهَا فَكَفَّارَتُهُ أَنْ يُصَلِّيَهَا إِذَا ذَكَرَهَا» . وَفِي رِوَايَةٍ: «لَا كَفَّارَة لَهَا إِلَّا ذَلِك»
Translation
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.)