Legal-rational authorities receive their ability to compel behavior by virtue of the office that they hold. It is the authority that demands obedience to the office rather than the office holder; Weber identified "rationally-created rules" as the central feature of this form of authority. Modern democracies are examples of legal-rational regimes. People also abide by legal-rational authority because it makes sense to do so for their own good, as well as for the greater good of society.
So that's it folks, the legal rationale,