Numbers 21:9 So Moses made a bronze serpent and set it on a pole. And if a serpent bit anyone, he would look at the bronze serpent and live. (ESV).
I’ve read a few places where the perception of this bronze or fiery brass serpent on a pole was something raised up as something to be semi-worshiped or believed in to attain healing. Context tells us otherwise. Key to the interpretation is its use by Jesus in John’s gospel:
John 3:14-15 And as Moses lifted up the serpent in the wilderness, so must the Son of Man be lifted up, that whoever believes in him may have eternal life.
John 12:32-33 And I, when I am lifted up from the earth, will draw all people to myself.” He said this to show by what kind of death he was going to die.
The gist is to signify a type and manner of death. The snake on a pole was not something glorious and magical to look at, but was more like that the snake was dead and even impaled by Moses upon his staff. This would indicate that God had power over and conquered the serpent and its sting, to the point that faith in Him rendered the snakes venom ineffective. So too is Christ on the cross a vision of the death of sin and that God has conquered even the power of sin to eternally kill. God in Christ is our object of worship, not only because of what we see accomplished as He was raised up on the cross, but that He transcends that moment to ascend to Heaven itself.
My point is this, don’t imagine the serpent on a pole story as something israel was instructed to worship separate from God. Although they do this later on so the staff must be put away, there is nothing to indicate that this was a form of worship at its instillation, but that it’s was an emblem of an enemy God had conquered, that people then and now can be grateful God has overcome.