Sunan Ibn Majah 696
The Book of the Prayer
حَدَّثَنَا جُبَارَةُ بْنُ الْمُغَلِّسِ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ قَتَادَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " مَنْ نَسِيَ صَلاَةً فَلْيُصَلِّهَا إِذَا ذَكَرَهَا " .
It was narrated that Anas bin Malik said:"The Messenger of Allah said: 'Whoever forgets a prayer, let him perform it when he remembers it
Grading: Al-Albani: Sahih · Muhammad Fouad Abd al-Baqi: Sahih · Zubair Ali Zai: Sahih
Text from the public-domain hadith-api dataset. Numbering follows that dataset and can differ by a few from some printed editions — check the wording, not only the number.