The first thing for which a person will be questioned on the Day of Judgment

عَنْ أَبِى ھُرَيْرَةَ، أَنَّ النَّبِىَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ

إِنَّ أَوَّلَ مَا يُحَاسَبُ بِهِ الْعَبْدُ يَوْمَ الْقِيَامَةِ صَلَاتُهُ وُجِدَتْ تَامَّةً وَإِنْ كَانَ انْتَقَصَ مِنْھَا شَىْءٌ قَالَ انْظُرُوْا هَلْ تَجِدُوْنَ لَهُ مِنْ تَطَوُّعٍ يُكَمَّلُ لَهُ مَا ضَيَّعَ مِنْ فَرِيضَةٍ مِنْ تَطَوُّعِهِ ثُمَّ سَائِرُ الْأَعْمَالِ تَجْرِىْ عَلَى حَسَبِ ذَلِكَ

Hazrat Abu Hurairah^ra narrates that the Holy Prophet, peace and blessings of Allah be upon him, said, “The first thing for which a person will be brought to account on the Day of Judgement will be his Salat. If it is found to be complete, then it will be recorded as complete and if anything is lacking, He will say, ‘Look and see if you can find any voluntary prayers with which to complete what he neglected of his obligatory prayers.’ Then the rest of his deeds will be reckoned in like manner.”

(Sunan al-Nasai, Kitab al-Salat, Hadith 466)