Answer:
The figurative language used in this poem is parallelism all throughout. If you want a specific line-by-line analysis, here it is:
Stop this day and night with me and you shall possess the origin of all poems,
- Alliteration - "you shall possess the origin of all poems" - You will independent and unique.
You shall possess the good of the earth and sun, (there are millions of suns left,)
- You will experience the greatness that life has to offer.
You shall no longer take things at second or third hand, nor look through the eyes of the dead, nor feed on the spectres in books,
- Parallelism - You will begin to think for yourself, not relying on the ideas of your ancestors, books, or those around you.
You shall not look through my eyes either, nor take things from me,
- Parallelism - You will not rely on my perspective, either.
You shall listen to all sides and filter them from yourself.
- You will be able to hear different opinions and stand out from them all.
These answers may not be exact as you might find different interpretations/meanings when looking at the poem as a whole. But I still hope this helps!