The Messenger of Allah ﷺ said, "The first thing for which a servant will be held accountable is his prayer. If he completed it, it will be recorded as complete. If he did not complete it, Allah will say, 'Look, do you find any voluntary prayers for My servant?' so that they may use them to complete his obligatory prayer. Then the zakat will be treated likewise, then the rest of the deeds will be assessed in the same manner."
قال حدثنا حسن بن موسى قال حدثنا حماد بن سلمة عن الأزرق بن قيس عن يحيى بن يعمر
قال رسول الله ﷺ أول ما يحاسب به العبد صلاته فإن كان أتمها كتبت له تامة وإن لم يكن أتمها قال الله عز وجل انظروا هل تجدون لعبدي من تطوع فتكملوا بها فريضته ثم الزكاة كذلك ثم تؤخذ الأعمال على حسب ذلك
Its isnad is sahih, its narrators are trustworthy and well-known. Azraq bin Qays Harithi is trustworthy, and Bukhari has narrated from him. Yahya bin Yamar, the judge of Marw, is trustworthy, and his hadith is found among the group of major hadith collectors. This hadith has preceded in similar wording at 9462.