18/Al-Kahf-21: And thus did We notified them (dwellers of the city), that they might know that Allah’s Promise is true and that as for the Hour (Doomsday), there is no doubt about it. They were disputing among themselves about their affair. They said: “Erect an edifice over them”. Their Lord best knows them. Those who prevailed in their affair said: “We will certainly raise a Masjid over them”.
18/Al-Kahf-22: And making conjectures without knowing at what is unknown, they will say: “(They are) three, the fourth of them being their dog”. They will say: “Five, the sixth of them being their dog”. And they will say: “Seven and the eighth of them is their dog”. Say: “Allah best knows their number, none of them knows except a few”. Do not argue about them except with an obvious (known) argument! Do not inquire about them asking (to explain) one of them!
18/Al-Kahf-23: And do not say of anything: “Surely I will do it tomorrow”.
18/Al-Kahf-24: (Say: I will do it) if Allah wills. And remember your Lord when you forget and say: “I hope my Lord makes me reach a nearer (more superior) level of Irshad (immaterial maturity) than this”.
18/Al-Kahf-25: And they remained in their Cave three hundred years, and exceeded by nine.
18/Al-Kahf-26: Say: “Allah knows best how long they remained”. To Him belongs the Unseen of the heavens and the earth. He sees and hears it (the Unseen) the best. There is none to be a friend for them besides Him. He does not make any one His associate in His Judgment.
18/Al-Kahf-27: Read what has been revealed to you of the Book of your Lord! There is none who can alter His Word. And you cannot find anyone to be turned to besides Him.