18:22
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."
Context in Surah Al-Kahf
Nearby ayahs help place verse 18:22 in sequence and meaning.
إِنَّهُمْ إِن يَظْهَرُوا۟ عَلَيْكُمْ يَرْجُمُوكُمْ أَوْ يُعِيدُوكُمْ فِى مِلَّتِهِمْ وَلَن تُفْلِحُوٓا۟ إِذًا أَبَدًا
Indeed, if they come to know of you, they will stone you or return you to their religion. And never would you succeed, then - ever."
وَكَذَٰلِكَ أَعْثَرْنَا عَلَيْهِمْ لِيَعْلَمُوٓا۟ أَنَّ وَعْدَ ٱللَّهِ حَقٌّ وَأَنَّ ٱلسَّاعَةَ لَا رَيْبَ فِيهَآ إِذْ يَتَنَـٰزَعُونَ بَيْنَهُمْ أَمْرَهُمْ ۖ فَقَالُوا۟ ٱبْنُوا۟ عَلَيْهِم بُنْيَـٰنًا ۖ رَّبُّهُمْ أَعْلَمُ بِهِمْ ۚ قَالَ ٱلَّذِينَ غَلَبُوا۟ عَلَىٰٓ أَمْرِهِمْ لَنَتَّخِذَنَّ عَلَيْهِم مَّسْجِدًا
And similarly, We caused them to be found that they [who found them] would know that the promise of Allah is truth and that of the Hour there is no doubt. [That was] when they disputed among themselves about their affair and [then] said, "Construct over them a structure. Their Lord is most knowing about them." Said those who prevailed in the matter, "We will surely take [for ourselves] over them a masjid."
وَلَا تَقُولَنَّ لِشَا۟ىْءٍ إِنِّى فَاعِلٌ ذَٰلِكَ غَدًا
And never say of anything, "Indeed, I will do that tomorrow,"
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."