In Henry V, Shakespeare knows that common soldiers experience war differently than the king and the nobility. After all, they're the ones who bear much of the burden of war and, if a battle is lost, they're likely to be killed while the king may be ransomed and his life spared. When Henry V orders his troops to invade France, his soldiers, many of whom are commoners, have no choice but to obey orders. They may not like it, and they may wish that they were back at home with their families or with friends at a favorite tavern, but their options are pretty limited. As a soldier named Williams puts it, "to disobey were against all proportion of subjection" (4.1.23).
Henry V suggests that, when a common soldier fights bravely in battle, he becomes ennobled.
Even though Henry tells his troops that they are all his "band of brothers," we know that the common soldiers will never be on equal footing with the king – it will always be their duty to obey him, even if his orders are unjust.