The narrator begins by addressing an "unravished bride of quietness" (1) who is portrayed on the urn. The speaker goes on to describe her as the "foster-child of silence and slow time" (2). This statement introduces the idea that the figures on the urn are part of an unchanging world. Also present on the urn are "pipes and timbrels" (10) to which the speaker says, "heard melodies are sweet, but those unheard / Are sweeter" (11-12). The speaker suggests that the audible melodies of the human world are inferior to the silent sounds of the eternal urn. The inaudible musical instruments are the first items on the immortal urn in a series that the speaker praises over their worldly counterparts. Looking upon two lovers, he says to the man, "never canst thou kiss,… / yet, do not grieve; / she [your lover] cannot fade" (17-19). Although the figure on the urn cannot "kiss" (17) as a human can, the speaker advises him not to worry as the object of his admiration will more importantly not "fade" (19). The "happy, happy boughs [of the urn]! that cannot shed / your leaves" (21-22) are likewise favored by the speaker for their unchanging nature over their seasonal equivalent.
However, soon the idea of immortality looses its appeal in the speaker's mind. The early signs of the transition come with the comment that the "for ever panting, and for every young" (27) world of the urn "leaves a heart high-sorrowful and cloyed." The definition of cloyed, "distaste at being supplied with too much of something originally pleasant," succinctly summarizes the realization that a never-ending supply of life can leave people unhappy with their existence. He also begins to see permanence through a different light as he continues to observe the urn. He notices a somber procession that, with his conception of eternity presented in the first three stanzas, will last forever. The speaker also sees a deserted town whose "streets for evermore / will silent be; and not a soul to tell / why thou art desolate" (38-40). The speaker sees the state of the town as permanently deserted, further highlighting his realization of the negative nature of eternity. This leads the speaker to the infamous final lines of the poem in which he states, "beauty is truth, truth beauty - that is all / ye know on earth, and all ye need to know" (49-50). The truth to which the speaker is referring is the truth of our condition; we are mortal creatures. "Beauty is truth" (49), the first ordering of the words, indicates that true beauty in the world comes from that which changes, that which is mortal. The speaker suggests through the second ordering, "truth beauty" (49), that the truth, the reality of change, is itself beautiful. These two interrelating ideas form our existence and the basis upon which Keats suggests that we live our lives.