The poet succeeds to write a quite convincing poem by using reasoning, metaphors, similes, and, most importantly (to me), very striking imagery. The former is a very direct and undisguised kind of reasoning. The poet says what he means when he means it. The language he uses to do this is beautiful: the words he chooses are intense and calm. This sets a contrast in the poem, but it also sort of balances it. It is a “fresh” and unique kind of language with a somewhat archaic vocabulary, which sometimes makes it difficult to understand the poem.
Some metaphors he uses are the following. First, the chariot: “Time’s winged chariot”, which apparently follows him everywhere, reminding him of (and referring to) the time passing (this is also an example of personification). He uses this image to kind of scare his mistress. “Let’s live while we are young”, he seems to be saying. Another metaphor is the one where he talks about the deserts of vast eternity, probably referring to death and/or afterlife. A different and interesting metaphor is the one where he proposes to “our time devour, than languish in his slow-chapt power”. If we understand that “slow-chapt power” as slowly devouring jaws, then it would make sense: the speaker prefers to eat up time rather than time eating him. To eat up time probably consists in doing something useful with it, something worth it. Like having sex with his mistress.
Similes are also used. The one I found to be the most beautiful of all was “Now therefore, while the youthful hue sits on thy skin like morning dew”. The image it awakes is peaceful and nice, in contrast to most of the other images that are presented in this poem. Imagery is one of the main features of this poem. It is always strong, very clear, and convincing. I think the most