“The Lord said to Moses, ‘Make a snake and put it up on a pole; anyone who is bitten can look at it and live.’ So Moses made a bronze snake and put it up on a pole. Then when anyone was bitten by a snake and looked at the bronze snake, he lived.” Numbers 21:8-9
When reading through the book of Numbers, we come across this incident, which seems rather bizarre. Not long before, God had given the Israelites a law – actually, the second of the Ten Commandments – saying they must not make anything in the form of something created, to be an idol and to be worshipped (Ex. 20:4-5). It was not the intention for the snake to be worshipped, although it did become an idol for the Israelites in later generations (see this post on 2 Kin. 18:4).
But a snake? The snake/serpent was the reason that sin was able to enter the world. Why would God tell Moses to make something that was the antithesis of Himself, for the children of Israel to look to for healing? Why not a dove, or a lamb?
The answer is given by Jesus in John 3:14-15. Moses lifting up the bronze snake (bronze being a symbol of judgement, thus, a picture of sin, the serpent, being judged) was a prophetic object lesson of how Jesus Himself would be lifted up on the cross, being judged for our sin. The Israelites only had to look at the bronze snake to be healed from the snake bites. They didn’t have to make offerings or pledge any money. So too with us: whoever looks to Him, believing, will be saved from the effects of the bite of sin.