Quran page 296

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."

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."

And never say of anything, "Indeed, I will do that tomorrow,"

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."

And they remained in their cave for three hundred years and exceeded by nine.

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."

And recite, [O Muhammad], what has been revealed to you of the Book of your Lord. There is no changer of His words, and never will you find in other than Him a refuge.