WELL ALLAH TOLD HIM WHEN HE WAS ALL ALONE AND UNABLE TO VERIFY IT.Exactly.
In the Quran myth Muhammad says Muslims are only allowed 4 wives, except those that marry women in Muhammad's family they are only allowed one wife... Oh but Muhammad is allowed 12 wives! Why? Well Allah told him when he was all alone and unable to verify it.
There you have it,,,he was either lying for his own wicked reasons , or in dire need of a psychiatrist. Nowadays any one expieriencing voices in their head, is a serious cause of concern for the rest of us.