My gracious lord, you look beyond him quite.
The Prince but studies his companions
Like a strange tongue, wherein, to gain the language,
’Tis needful that the most immodest word
Be looked upon and learned; which, once attained,
Your Highness knows, comes to no further use
But to be known and hated. So, like gross terms,
The Prince will, in the perfectness of time,
Cast off his followers, and their memory
Shall as a pattern or a measure live,
By which his Grace must mete the lives of others,
Turning past evils to advantages.
(Act 4, scene 3, lines 72–84)

The Earl of Warwick speaks these lines in response to one of King Henry’s apocalyptic visions of England’s future under his son Harry’s reign. Warwick’s main aim here is to offer a corrective to the king’s overly pessimistic view, which fundamentally misconstrues the prince’s true nature. Henry believes Harry to be an unrepentant reprobate who continues to spend an undue amount of time in the seedy district of Eastcheap. Warwick, by contrast, makes the counterargument that Harry treats his time in the taverns and brothels of London as an opportunity to study the people he will one day rule. This is a line of reasoning that Harry himself presented in Henry IV, Part 1, and particularly in a scene where he joyfully describes how some recent acquaintances in the tavern introduced him to exciting new lingo. Harry is certainly a student of his subject, and he is both literally and figuratively learning the language of the commoners, as Warwick suggests in this passage.

Of course, as Warwick also suggests, even though Harry may delight at learning “the most immodest word,” eventually it will no longer serve him. At that time, he will turn away from tavern life and “cast off his followers.” Warwick’s remark clearly anticipates the final scene of the play, where Harry, newly crowned as King Henry V, will formally banish Falstaff from his presence. It’s also notable that Warwick takes on a biblical register when he describes how Harry will reform himself “in the perfectness of time.” For one thing, the very notion of Harry’s eventual reformation connects him to the biblical parable of the Prodigal Son related in Luke 16:19–31. For another, Warwick’s language strongly recalls a passage from Galatians 4:4: “But when the fullness of time was come, God sent forth his Son.” In this way, Warwick makes an implicit link between Harry and Christ, who in his “Grace” will succeed in “turning past evils into advantages.” Warwick’s account of Harry’s behavior thus clearly positions the prince as a worthy—even Christlike—heir to the throne.