How we cite our quotes:
From low to high doth dissolution climb,
And sink from high to low, along a scale (lines 1-2)
In daily speech and especially in literature, the verbs "climb" and "sink" are frequently used together to describe the motion of the sun. The rising and falling of the sun, of course, is a fundamental image of passing time.
Which they can hear who meddle not with crime,
Nor avarice, nor over-anxious care. (lines 5-6)
Think of how a busy professional person – a banker or lawyer perhaps – might relate to time, compared to a certain British poet who lives a quiet life in the countryside. The speaker says that stressed or selfish people are too absorbed in their own immediate aims to understand that the very earth they stand on is sinking, figuratively speaking of course.
but her outward forms that bear
The longest date do melt like frosty rime, (lines 7-8)
Older things in particular tend to melt away like frost. Hm…let us think…now why would an aging poet be worried about what happens to old– Ah, now we get it.