* The constant and inevitable passage of time "as the slow dark months of winter merge into spring" and "the relentless procession of the years".
* The monotony and repetitiveness of life, symbolised by the "grey procession" of the days.
* The feeling of being trapped and suffocated by the sameness and lack of stimulation in life, expressed through the imagery of "walls" and "prison".
* The inability to escape or break free from this oppressive existence, conveyed by the metaphor of being "chained" by the "unyielding bars" of time.
* The sense of helplessness and hopelessness, highlighted by the speaker's lack of agency and control over the situation, as they feel themselves to be "swept away" by the relentless flow of time.
* The futility and meaninglessness of existence, emphasised by the speaker's use of phrases such as "the vain reiteration of the days" and "the endless repetition of the years".
* The speaker's despair and longing for release from this mundane and stifling existence, as they cry out "Deliver me!" in the final line of the second stanza.