It is revelation to the first person only, and hearsay to every other, and, consequently, they are not obliged to believe it.
It is a contradiction in terms and ideas to call anything a revelation that comes to us at second hand, either verbally or in writing.
Revelation is necessarily limited to the first communication.

After this, it is only an account of something which that person says was a revelation made to him; and though he may find himself obliged to believe it, it cannot be incumbent on me to believe it in the same manner, for it was not a revelation made to me, and I have only his word for it that it was made to him.
When Moses told the children of Israel that he received the two tables of the commandments from the hand of God, they were not obliged to believe him, because they had no other authority for it than his telling them so; and I have no other authority for it than some historian telling me so, the commandments carrying no internal evidence of divinity with them.

They contain some good moral precepts such as any man qualified to be a lawgiver or a legislator could produce himself, without having recourse to supernatural intervention.

[NOTE: It is, however, necessary to except the declamation which says that God 'visits the sins of the fathers upon the children'.

This is contrary to every principle of moral justice .-- Author.] When I am told that the Koran was written in Heaven, and brought to Mahomet by an angel, the account comes to near the same kind of hearsay evidence and second hand authority as the former.