The exchange of thrown gages at the beginning of the scene hearkens back to Act I, scene i, when Bolingbroke and Mowbray challenged each other to the duel that resulted in Richard banishing them both. In reflecting this earlier scene, however, Act IV, scene i also alters it. For the unacknowledged secret that lay behind Bolingbroke's accusation and banishment--the fact that King Richard himself was behind Gloucester's murder--has now been brought into the light. Now that Richard has been deposed, his past sin can be brought back as a crime with which to charge him. This scene also foreshadows the way in which Bolingbroke himself will re-enact Richard's crime and his fall, when he, as King Henry IV, becomes partly responsible for Richard's murder in Act V, scene v.
The Bishop of Carlisle's speech is placed centrally in the scene (between Bagot and Aumerle's challenges and Richard's abdication), and is one of the play's key monologues. This speech is the final culmination and most eloquent example of the series of warnings, curses and dark prophecies that have been accumulating since the play's beginning--but the darkness that was, at first, foretold for Richard is now being prophesied for Bolingbroke.
Carlisle starts out by invoking a familiar theme: a king's divine sanction and God's anger at the usurpation of his throne. Carlisle calls the king "the figure of God's majesty, / His captain, steward, deputy elect, / Anointed, crowned, planted many years" (125-27), and says that no subject has the right to overthrow his king. We hear echoes here of earlier speeches, such as Gaunt's reference to the king as God's "deputy anointed in His sight" in Act I, scene ii, York's defense of the king's rights in Act II, scene iii, and Richard's own claim that "Not all the water in the rough rude sea / Can wash the balm off from an anointed king" (III.ii.54-55). Carlisle then follows this by prophesying destruction for the usurper--a curse similar to that which John of Gaunt laid on Richard in Act II, scene i, and which Richard himself delivered to Bolingbroke in Act III, scene iii. If Bolingbroke is crowned king, Carlisle prophesies, civil war will tear the realm apart: "Disorder, horror, fear, and mutiny / Shall here inhabit, and this land be call'd / The field of Golgotha and dead men's skulls" (142-44). Although Bolingbroke and his men ignore the prophecy and arrest Carlisle on charges of treason, his dark prophecy hangs over the rest of the play.
King Richard's several extraordinary speeches during the scene of his abdication are among the most famous passages in the play and are worth reading carefully. The first is built around one of Richard's theatrical gestures: Richard, even as he proffers the crown to Bolingbroke, is not quite ready to let go of it. As the two stand staring at each other, each with one hand resting upon the crown, Richard compares the crown to a well which balances the two princes like a pair of buckets, full of water: as Bolingbroke pours out his water into Richard, causing him to sink, Bolingbroke himself rises higher.
When Bolingbroke asks him straightforwardly if he is willing to turn over the crown, Richard enters into a long soliloquy in which he formally strips himself of his kingship: "With mine own hands I give away my crown, / With mine own tongue deny my sacred state" (208-9).
Finally, comparing himself to a snowman who stands before the sun (since Bolingbroke, now king, has the right to refer to himself as the sun), Richard wonders aloud whether he has melted away and whether he has any identity any more. He calls for a looking-glass (a mirror) so that he may behold whether he still exists. Staring at the face which is no longer the face of a king, he is overcome. He dramatically smashes the mirror upon the floor, shattering his reflection into shards. His meaning is that Bolingbroke's usurpation of his kingship has symbolically, and perhaps literally, destroyed him: "Mark, silent king, the moral of this sport--How soon my sorrow hath destroyed my face" (290-91).