Sahih Muslim 684 a
Qatada reported from Anas b. Malik that the Messenger of Allah (ﷺ) said:
He who forgets the prayer should say it when he remembers it, there is no explation for it, except this. Qatada said: (Allah says)" And observe prayer for remembrance of Me"
حَدَّثَنَا هَدَّابُ بْنُ خَالِدٍ، حَدَّثَنَا هَمَّامٌ، حَدَّثَنَا قَتَادَةُ، عَنْ أَنَسِ بْنِ مَالِكٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏
"‏ مَنْ نَسِيَ صَلاَةً فَلْيُصَلِّهَا إِذَا ذَكَرَهَا لاَ كَفَّارَةَ لَهَا إِلاَّ ذَلِكَ ‏"‏ ‏.‏ قَالَ قَتَادَةُ وَأَقِمِ الصَّلاَةَ لِذِكْرِي ‏.‏