Moreover, we have seen Hal gradually reject Falstaff as a father figure; he replaces him first (briefly) with his own father, Henry IV, and later with the Lord Chief Justice. So it is appropriate that the Justice finally be sent back in to finish Hal's dirty work, triumphing at last in the eternal quarrel between himself and Falstaff (and, symbolically, between the forces of order and anarchy).
However, it is difficult not to have mixed feelings about Hal's "miraculous" transformation. First, Falstaff is too sympathetic a character for us not to be a little disappointed by Hal's rejection. In addition, it is not only Falstaff's hopes for wealth and power, but also his affection for his young friend, that Hal rejects. If we read Falstaff as genuinely caring for Hal, then his feeling of betrayal must be enormous. When he greets the new King, after riding hard across the countryside to reach him, he cries, "King Hal, my royal Hal! . . . God save thee, my sweet boy! ... My King! My Jove! I speak to thee, my heart!" (41-46). Hal's cold and silencing reply--"I know thee not, old man"--cuts to the heart.
In these scenes, it also becomes evident that Hal has taken the Lord Chief Justice as a model for his speech as well as his character: Hal now talks in more regal and powerful language, shows less of a sense of humor, and appears to have given up punning entirely. It is clear that Hal wants to reject all of the trappings of his former identity: "Presume not that I am the thing I was," he says to Falstaff, "For God doth know . . . / That I have turn'd away my former self" (56-58). As the "tutor and the feeder of my riots" (62), Falstaff no longer has a place in Hal's new life. In the end, for better or worse, Hal feels that he has traded chaos for order and freedom for responsibility and that, as a result, he has become a good king.
Prince John's closing comments about France may seem a little out of place, but Shakespeare is simply paving the way for this play's sequel, Henry V, which deals with the invasion of France by the new king.