(19) باب السَّهْوِ فِي الصَّلاَةِ وَالسُّجُودِ لَهُ
'Abdullah (b. Mas'ud) reported:
The Apostle of Allah (ﷺ) said five rak'ahs of the noon prayer and when he completed the prayer, It was said to him: Has there been (commanded) an addition In prayer? He said: What is it? They said: You have said five rak'ahs, so he performed two prostrations.
Reference: Sahih Muslim 572 h
In-book reference: Book 5, Hadith 119
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1175