like i've posted.
I claim the post above to be my personal view.
And it is upon a protestant point of view which i stood by.
I suppose you are referring to these verses?
Interestingly the serpent in v.8 was referred to 1.serpent, fiery
serpent
poisonous serpent (fiery from burning effect of poison) or 2.
seraph, seraphim majestic beings with 6 wings, human hands or
voices in attendance upon God.
Verse 9 refers to 1.
Numbers 21:8 And the LORD said unto Moses, Make thee a fiery
serpent, and set it upon a pole: and it shall come to pass, that
every one that is bitten, when he looketh upon it, shall
live.
21:9 And Moses made a serpent of brass, and put it upon a pole, and
it came to pass, that if a serpent had bitten any man, when he
beheld the serpent of brass, he lived.
It is referenced also on
John 3:14 Just as Moses lifted up the serpent in the wilderness, so
the Son of Man must be lifted up,
3:15 so that everyone who believes in Him will have eternal
life.
_______
Contextually,
the main subject is Moses, God and the isrealites.
The erection of the long brass pole which have the representation
of a serpent bears little importance. Again, it comes to different
emphasis of the verses.
A foreshadow of the Christ work.
Because Isrealites disobeyed God - they were judged and many
died.
Because Moses prayed and interceded for the isrealites who sinned
against God - God forgave them 'On the account of Moses
intercession.
Because God forgave them - God commanded Mose to build a pole which
bears the serpent.
Isrealites got healed not because of the pole - But because of the
act of looking at the pole which 
God have
commanded.
Because by the act of trust and faith in God's command. They are
healed.
Further notes
John Wesley's Explanatory Notes
A fiery serpent - That is, the figure of a serpent in brass, which
is of a fiery colour.
This would require some time: God would not speedily take off the
judgment, because he saw they were not throughly humbled.
Upon a pole - That the people might see it from all parts of the
camp, and therefore the pole must be high, and the serpent
large.
When he looketh - This method of cure was prescribed, that it might
appear to be God's own work, and not the effect of nature or art:
and that it might be an eminent type of our salvation by
Christ.
The serpent signified Christ, who was in the likeness of sinful
flesh, though without sin, as this brazen serpent had the outward
shape, but not the inward poison, of the other serpents: the pole
resembled the cross upon which Christ was lifted up for our
salvation: and looking up to it designed our believing in
Christ.
