"‏ إِنَّ أَوَّلَ مَا يُحَاسَبُ بِهِ الْعَبْدُ يَوْمَ الْقِيَامَةِ مِنْ عَمَلِهِ صَلاَتُهُ فَإِنْ صَلُحَتْ فَقَدْ أَفْلَحَ وَأَنْجَحَ وَإِنْ فَسَدَتْ فَقَدْ خَابَ وَخَسِرَ فَإِنِ انْتَقَصَ مِنْ فَرِيضَتِهِ شَيْءٌ قَالَ الرَّبُّ عَزَّ وَجَلَّ انْظُرُوا هَلْ لِعَبْدِي مِنْ تَطَوُّعٍ فَيُكَمَّلَ بِهَا مَا انْتَقَصَ مِنَ الْفَرِيضَةِ ثُمَّ يَكُونُ سَائِرُ عَمَلِهِ عَلَى ذَلِكَ ‏"

"I arrived in Al-Madinah and said: 'O Allah! Facilitate me to be in a righteous gathering.'" He said: "I sat with Abu Hurairah and said: 'Indeed I asked Allah to provide me with a righteous gathering. So narrate a hadith to me which you heard from Allah's Messenger (ﷺ) so that perhaps Allah would cause me to benefit from it.' He said: 'I heard Allah's Messenger (ﷺ) say: "Indeed the first deed by which a servant will be called to account on the Day of Resurrection is his Salat. If it is complete, he is successful and saved, but if it is defective, he has failed and lost. So if something is deficient in his obligatory (prayers) then the Lord, Mighty and Sublime says: 'Look! Are there any voluntary (prayers) for my worshipper?' So with them, what was deficient in his obligatory (prayers) will be completed. Then the rest of his deeds will be treated like that."