Numbers 21:4-8

Then they set out from Mount Hor by the way of the Red Sea, to go around the land of Edom; and the people became impatient because of the journey.

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.”