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. Num. 21:9

There is a world of revelation in that verse and in its symbolism.

And Moses… Moses was the one through whom God brought the Law, the conscious knowledge of our sin against a Holy God. Before the law there was no sin. For with the law came sin. "For until the law sin was in the world: but sin is not imputed when there is no law. Rom. 5:13" And again, "For I was alive without the law once: but when the commandment came, sin revived, and I died. Rom. 7:9"

… Moses made a serpent… The lawgiver made the serpent. The lawgiver made the thing that would bring death to us. "The sting of death is sin; and the strength of sin is the law. 1 Cor 15:56"

… of brass… Brass is the symbol of our affliction. The oxen wore brass shoes to tread out the wheat. It was the weight (the brass) upon the back of the wheat (the stuff that the bread of life is made of) that separates the fruit on the inside from its outer shell, the body, the flesh. Affliction has a way of refining. The knowledge of our sin has a way of separating the useful part in us from the part that needs to be burned in the fire.

… and put it on a pole… This serpent that injects the poison and brings to light the knowledge or our impending death, has been killed and is no longer a threat to us. This is the part that is not seen nor understood by most though this is placed on a pole with a cross beam and lifted up in plain view. This light has not been hidden under a bushel but is placed high for all to see.

… and it came to pass… at a time, at a perfect time, between eternity past and eternity forward, at just the right time, having killed this serpent (not taken it away) it was lifted up on a pole and the knowledge of his death was made visible as a spectacle for all to see.

… that if a serpent had bitten any man… that if by knowledge of the law our conscience (the knowledge of good and evil) was awakened by the bite of the serpent and we saw our approaching death…

… that… when we beheld the serpent of brass… When we saw the state of our enemy. That he was trampled under foot, with his sting no longer a threat and now made a spectacle. That when he saw (by faith) that someone had taken him away and brought to naught death himself.

… he lived (and did not die). The key is in the looking and beholding. For now we see dimly, but then we shall see face to face. "Looking unto Jesus the author and finisher of our faith; who for the joy that was set before him endured the cross… Heb. 12:2" It was upon the pole that He took the sting to himself on our behalf and thus defeated our enemy.

Now, the knowledge or our sin brought about by the law is very real and threatening. Many, when bitten, run in many directions crying for help and even hiding and closing their eyes. But some run to the pole and behold the serpent and long with eyes of faith to know who killed the serpent and trust in Him.

How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God? Heb. 9:14