" كَفَّارَتُهَا أَنْ يُصَلِّيَهَا إِذَا ذَكَرَهَا "
It was narrated that Anas said: "The Messenger of Allah (ﷺ) was asked about a man who slept and missed the prayer, or forgot it. He said: 'The expiation for that is to pray it when he remembers it.'"