Q 31:24

And whosoever submits his face (himself) to Allah, while he is a Muhsin, then he has grasped the most trustworthy handhold. And to Allah return all matters for decision (22)And whoever disbelieves, let not his disbelief grieve you. To Us is their return, and We shall inform them what they have done. Verily, Allah is the All-Knower of what is in the breasts (23)We let them enjoy for a little while, then in the end We shall oblige them to (enter) a great torment.) Allah tells us that whoever submits his face to Allah, i.e., does deeds sincerely for His sake, submits to His commandments and follows His Law (24) وَهُوَ مُحْسِنٌ (while he is a Muhsin) i.e., doing what his Lord has commanded and abstaining from what He has forbidden, فَقَدِ اسْتَمْسَكَ بِالْعُرْوَةِ الْوُثْقَىٰ (then he has grasped the most trustworthy handhold.) means, he has received a firm promise from Allah that He will not punish him. وَإِلَى اللَّهِ عَاقِبَةُ الْأُمُورِ - وَمَنْ كَفَرَ فَلَا يَحْزُنْكَ كُفْرُهُ ۚ (And to Allah return all matters for decision. And whoever disbelieves, let not his disbelief grieve you.) means, 'do not grieve over them, O Muhammad, because they disbelieve in Allah and in the Message you have brought, for their return will be to Allah and He will tell them what they used to do,' i.e., He will punish them for it. إِنَّ اللَّهَ عَلِيمٌ بِذَاتِ الصُّدُورِ (Verily, Allah is the All-Knower of what is in the breasts.) and nothing whatsoever is hidden from Him. Then Allah says: نُمَتِّعُهُمْ قَلِيلًا (We let them enjoy for a little while,) means, in this world, ثُمَّ نَضْطَرُّهُمْ (then in the end We shall oblige them) means, 'We shall cause them,' إِلَىٰ عَذَابٍ غَلِيظٍ (to (enter) a great torment.) means, a torment that is terrifying and difficult to bear. This is like the Ayah, إِنَّ الَّذِينَ يَفْتَرُونَ عَلَى اللَّهِ الْكَذِبَ لَا يُفْلِحُونَ - مَتَاعٌ فِي الدُّنْيَا ثُمَّ إِلَيْنَا مَرْجِعُهُمْ ثُمَّ نُذِيقُهُمُ الْعَذَابَ الشَّدِيدَ بِمَا كَانُوا يَكْفُرُونَ ("Verily, those who invent a lie against Allah, will never be successful." Enjoyment in this world! and then unto Us will be their return, then We shall make them taste the severest torment because they used to disbelieve.)(10:69-70)