Numbers 21:5-9

So the people spoke against God and Moses: “Why have you brought us up from Egypt to die in the wilderness? For there is no food and no water, and we are disgusted with this miserable food.” The Bronze Serpent

Then the Lord sent fiery serpents among the people and they bit the people, so that many people of Israel died.

So the people came to Moses and said, “We have sinned, because we have spoken against the Lord and against you; intercede with the Lord, that He will remove the serpents from us.” And Moses interceded for the people.

Then the Lord said to Moses, “Make a fiery serpent, and put it on a flag pole; and it shall come about, that everyone who is bitten, and looks at it, will live.”

So Moses made a bronze serpent and put it on the flag pole; and it came about, that if a serpent bit someone, and he looked at the bronze serpent, he lived.