"A soul shall know what it has sent forth and left behind," meaning: what it sent forth of good or evil, and what it left behind of a good sunnah (practice) that was acted upon after him, for which he receives a reward equal to those who acted upon it without their rewards being diminished in the slightest, or of a bad sunnah that was acted upon after him, for which he bears a burden equal to those who acted upon it without their burdens being diminished in the slightest.
﴿عَلِمَتْ نَفْسٌ مَا قَدَّمَتْ وَأَخَّرَتْ﴾ مَا قَدَّمَتْ مِنْ خَيْرٍ أَوْ شَرٍّ، وَمَا أَخَّرَتْ مِنْ سُنَّةٍ حَسَنَةٍ، فَعُمِلَ بِهَا بَعْدَهُ فَلَهُ مِثْلُ أَجْرِ مَنْ عَمِلَ بِهَا لَا يُنْقَصُ مِنْ أُجُورِهِمْ شَيْئًا، أَوْ سُنَّةٍ سَيِّئَةٍ فَعُمِلَ بِهَا بَعْدَهُ فَعَلَيْهِ مِثْلُ وِزْرِ مَنْ عَمِلَ بِهَا لَا يُنْقَصُ مِنْ أوزارهم شَيْئا.