Numbers 21:5-8

And the people spoke against God and against Moses, Why have you brought us out of Egypt to die in the wilderness? For there is no bread, neither is there any water, and we loathe this light (contemptible, unsubstantial) manna. Then the Lord sent fiery (burning) serpents among the people; and they bit the people, and many Israelites died. And the people came to Moses, and said, We have sinned, for we have spoken against the Lord and against you; pray to the Lord, that He may take away the serpents from us. So Moses prayed for the people. And the Lord said to Moses, Make a fiery serpent [of bronze] and set it on a pole; and everyone who is bitten, when he looks at it, shall live.