Allah says: "They will say," meaning the People of the Scripture will say, "Three, the fourth of them is their dog; and they say, 'Five, the sixth of them is their dog,' guessing at the unseen." Al-Suddi said: It means guessing based on conjecture.
Muhammad said: The meaning is that they say that based on conjecture without certainty. Zuhayr said:
(And war is nothing but what you have known and tasted ... And it is not about it merely speculative talk)
Regarding His saying: "And they say, 'Seven, and the eighth of them is their dog.' Say, 'My Lord is most knowing of their number. None knows them except a few.'" Qatada said: Except a few people. It was mentioned to us that Ibn Abbas used to say: I am among those few whom Allah has excepted; they were seven, and the eighth of them was their dog.
He said: "So do not argue about them," Allah says to the Prophet: Do not argue with the People of the Scripture regarding the Companions of the Cave "except with an apparent argument," meaning: except for what I have informed you of, according to the exegesis of al-Hasan.
Muhammad said: The meaning is: Issue a fatwa regarding their story according to the apparent [truth] that has been revealed to you. "And do not consult about them," regarding the Companions of the Cave, "among them anyone," from the Jews.