Brothers can’t give each other justice. They just can’t, no matter how much they try, no matter how much they want to.
Brothers may be slightly older or younger, slightly bigger or smaller, but they come from the same stock, the same species, the same branch. They are very much alike—so much alike that what helps or hurts one brother has a similar effect on the other brother.
Justice must come from above. It can’t traverse brothers.
For punishment or reward, opportunity or confinement, brothers can’t find justice between each other separately. Brotherly justice can only be achieved together.