The Meaning of Ad-Din
Ad-Din means the reckoning, the reward or punishment. Similarly, Allah said,
﴿ يَوۡمَٮِٕذٍ۬ يُوَفِّيہِمُ ٱللَّهُ دِينَهُمُ ٱلۡحَقَّ ﴾
(On that Day Allah will pay them the (Dinahum) recompense (of their deeds) in full) (24:25), and,
﴿ أَءِنَّا لَمَدِينُونَ ﴾
(Shall we indeed (be raised up) to receive reward or punishment (according to our deeds)) (37:53). A Hadith stated,
« الْكَيِّسُ مَنْ دَانَ نَفْسَهُ وَعَمِلَ لِمَا بَعْدَ الْمَوتِ »(The wise person is he who reckons himself and works for (his life) after death.) meaning, he holds himself accountable. Also, `Umar said, "Hold yourself accountable before you are held accountable, weigh yourselves before you are weighed, and be prepared for the biggest gathering before He Whose knowledge encompasses your deeds,
﴿ يَوۡمَٮِٕذٍ۬ تُعۡرَضُونَ لَا تَخۡفَىٰ مِنكُمۡ خَافِيَةٌ۬ ﴾
(That Day shall you be brought to Judgment, not a secret of yours will be hidden) (69:18).''
﴿ إِيَّاكَ نَعۡبُدُ وَإِيَّاكَ نَسۡتَعِينُ ﴾
(5. You we worship, and You we ask for help.) (1:5)