Both Henry IV Part 1 and Part 2 offer an elaborate meditation on kingship. In Part 2, Shakespeare focuses on the anxieties surrounding succession and the transfer of power between father and son. For Henry IV, kingship has been an exhausting and draining experience. Because Henry usurped the crown in Richard II, he spends most of his reign defending his position and worrying about what will happen when his unruly son, Hal, takes over. When Hal replaces his father and becomes Henry V, his position is more legitimate because he's inherited the throne by lineal succession. At the same time, Hal must prove that, despite his wild youth, he's fit to rule the country.
Because Henry IV usurped the throne from a Richard II, his power and legitimacy are less stable than that of a monarch who inherits the throne by lineal succession – by rebelling against and deposing a king, Henry IV has paved the way for future rebellion.
Although King Henry IV worries about what will become of the kingdom, his anxieties about Prince Hal's succession to the throne are finally put to rest before he dies.