Surah Al-Kahf 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 [i.e., people] 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 Muḥammad], "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."

Translation: Saheeh International

Tafsir

They will say that is some of those disputing the number of the youths of the cave at the time of the Prophet s in other words some of these will say that they the youths were ‘Three; their dog the fourth of them’; and they some others among them will say ‘Five; …

Excerpt from Tafsir al-Jalalayn, commentary on 18:22, via Quran.com. The reader has the full commentary and 9 more tafsirs.