(9) باب الْمُحَاسَبَةِ عَلَى الصَّلاَةِ .
It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said:
"The first thing for which a person will be brought to account will be his Salah. If it is complete (all well and good), otherwise Allah will say: 'Look and see if My slave did any voluntary prayer.' If he is found to have done voluntary prayers, his obligatory prayers will be completed therewith."
Reference: Sunan an-Nasa'i 467
In-book reference: Book 5, Hadith 20
English translation: Vol. 1, Book 5, Hadith 468