When we were kids on a long road trip, we would end up complaining loudly about the time, the length of the journey, each other and life in general. The parental reaction was “If you don’t stop I’ll give you something to whinge about!”
Something like this happened in the wilderness where the Israelites wandered for forty years. They wouldn’t stop whinging about their lot. Fed up, God sent venomous snakes into the camp. There were many deaths from snake-bite, so they turned to Moses for help. God told Moses to make an image of a snake from bronze and erect it high on a pole. All people had to do was look at it when bitten and they would be safe.
There are other reasons for the image of a snake on a stick that is sometimes on our medicine bottles (see Aesculapius) .
However Christian imagery picks up this bizarre story as an image of the work of Christ on the cross (see John 3:14). The ancient wisdom underpinning all this is to suggest that it is looking into our malady that we find our cure. It is also found in the gospel’s double entendre in that “raising Christ up” (on the cross? from the tomb?) God’s purpose for us all is accomplished.