The Prophet ﷺ said, "The first thing for which a servant will be called to account on the Day of Resurrection is his prayer. If he has performed it completely, it will be recorded for him as complete. If he has not performed it completely, Allah, the Exalted, will say to His angels, 'Look, do you find any voluntary prayers for My servant?' Then they will use them to make up what he neglected of his obligatory prayers. The rest of his deeds will be judged in the same manner."
عن النبي ﷺ قال: أول ما يحاسب به العبد يوم القيامة صلاته، فإن أكملها كتبت له كاملة، فإن لم يكن أكملها، قال الله سبحانه لملائكته: انظروا هل تجدون لعبدي من تطوع؟ فأكملوا بها ما ضيع من فريضته، ثم توخذ الأعمال على حسب ذلك.
Ibn Majah (1426) narrated it from Ahmad bin Saeed Darimi, who said, Sulayman bin Harb told us, who said, Hammad bin Salama told us, from Dawud bin Abu Hind, from Zurara bin Awfa, from Tamim Dari, who mentioned the same account. Its isnad is sahih. Abu Dawud (866) also narrated it from Musa bin Ismail, who said Hammad told us the same, but referred to the wording of Abu Hurairah which will come later. Hakim also recorded it in Mustadrak (1/262–263) through the route of Musa bin Ismail with the same wording, and said, "It is a sahih corroborating witness meeting the standard of Muslim."