Islam's army

In the 6^th century, their were no modern governments, nor any real standing armies. (Except maybe the Roman army) At that time, armies were generated on an as needed basis. Religion was frequently a uniting factor. Islam is the only entity that I know of this is still fielding an army in this fashion. Throughout history, tactics of guerrilla warfare are the mark of an inferior fighting force. Terrorism is the natural product of such a backward combination of a religious and nationalist entity. This method of generating an armed force even acts like the age from which it began: 7^th century it. Be-headings, cutting off the hands, gouging out eyes, whipping and stoning are classic punishment from that same time period. This 'army' does not recognize any modern government nor any of the modern rules of warfare.