The Cave
إِلَّآ أَن يَشَآءَ ٱللَّهُ ۚ وَٱذْكُر رَّبَّكَ إِذَا نَسِيتَ وَقُلْ عَسَىٰٓ أَن يَهْدِيَنِ رَبِّى لِأَقْرَبَ مِنْ هَـٰذَا رَشَدًا
Except [when adding], "If Allah wills." And remember your Lord when you forget [it] and say, "Perhaps my Lord will guide me to what is nearer than this to right conduct."
Nearby ayahs help place verse 18:24 in sequence and meaning.
سَيَقُولُونَ ثَلَـٰثَةٌ رَّابِعُهُمْ كَلْبُهُمْ وَيَقُولُونَ خَمْسَةٌ سَادِسُهُمْ كَلْبُهُمْ رَجْمًۢا بِٱلْغَيْبِ ۖ وَيَقُولُونَ سَبْعَةٌ وَثَامِنُهُمْ كَلْبُهُمْ ۚ قُل رَّبِّىٓ أَعْلَمُ بِعِدَّتِهِم مَّا يَعْلَمُهُمْ إِلَّا قَلِيلٌ ۗ فَلَا تُمَارِ فِيهِمْ إِلَّا مِرَآءً ظَـٰهِرًا وَلَا تَسْتَفْتِ فِيهِم مِّنْهُمْ أَحَدًا
They will say there were three, the fourth of them being their dog; and they will say there were five, the sixth of them being their dog - guessing at the unseen; and they will say there were seven, and the eighth of them was their dog. Say, [O Muhammad], "My Lord is most knowing of their number. None knows them except a few. So do not argue about them except with an obvious argument and do not inquire about them among [the speculators] from anyone."
وَلَا تَقُولَنَّ لِشَا۟ىْءٍ إِنِّى فَاعِلٌ ذَٰلِكَ غَدًا
And never say of anything, "Indeed, I will do that tomorrow,"
وَلَبِثُوا۟ فِى كَهْفِهِمْ ثَلَـٰثَ مِا۟ئَةٍ سِنِينَ وَٱزْدَادُوا۟ تِسْعًا
And they remained in their cave for three hundred years and exceeded by nine.
قُلِ ٱللَّهُ أَعْلَمُ بِمَا لَبِثُوا۟ ۖ لَهُۥ غَيْبُ ٱلسَّمَـٰوَٰتِ وَٱلْأَرْضِ ۖ أَبْصِرْ بِهِۦ وَأَسْمِعْ ۚ مَا لَهُم مِّن دُونِهِۦ مِن وَلِىٍّ وَلَا يُشْرِكُ فِى حُكْمِهِۦٓ أَحَدًا
Say, "Allah is most knowing of how long they remained. He has [knowledge of] the unseen [aspects] of the heavens and the earth. How Seeing is He and how Hearing! They have not besides Him any protector, and He shares not His legislation with anyone."