Me and my friend have a bet i say if i have two command knights on the field and no other creatures that neither of my command knights could be attacked, but my friend says that he can still attack the command kights. So who is right?

he can't attack either. command knight says it cannot be attacked if there is another monster on the field, whichever one he wants to attack, he can't, since there is another monster on the field. it's a "lock"

uncsteve is right..... its a lock, as is 2 marauding capis, 2 Solar flare dragon etc... 2 of each say that they have to be attacked or can't be attacked either would make a soft lock