So, in Numbers chap 21, verses 4-9 we get the account of the people Israel having a moan at Moses and God (again!) because something isn’t quite right, and they’ve forgotten (again!) that prior to the Exodus they were an enslaved nation for like, ages (something like 450yrs but you can correct me if you want).
Anyway, the point being- they turn against God, challenging his right to be their God. Which always a risky idea- its on a par with the claim ‘God is dead’: if God is dead, what kind of god can die and why were you worshipping him anyway? (so the outcome is that you look like an idiot) or if God isn’t dead, you either get frazzled (or bitten by a snake as in this example) or else you’re let off (like those clips of lion prides where the cheeky cub bites the males tail and you’re thinking ‘you have no idea how tolerant he’s being…)
So, the snakes… whether you view their arrival as God’s response to their sin/rudeness or whether God’s protection was lifted, or it was just one of those things that happened… a plague of snakes anywhere isn’t much fun, whether it be in a desert or on a plane (i’ve never seen the film ‘Snakes on a Plane’ as i don’t even like a plague of snakes on the TV screen, but i’m told its quite… snakey)
And then we get the outcome- they repent, Moses prays and God tells him to make a metal snake (which is the origin of the snake on various medical badges, i think)- anyone who looks at it after being bitten won’t die. the snakes are still around, their still poisonous, but there is a way out- one that involves having faith, just as the people had lost their faith in God at the start of the passage… he’s quite clever, God.
Faith in something that you can see brings an outcome that is not directly connected to it- you look at a metal snake, the poison in your body doesn’t kill you. Or to cite the comparison that a teacher used a few years later- you believe that a man lifted up can die for your sins, and you are forgiven all that you’ve done; pretty cool, eh? (BTW- see John’s Gospel, chap 3 for Nicodemus’ lesson at night school)