Numbers 21:7-9

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 take away the serpents from us.” So Moses prayed for the people. And the LORD said to Moses, “Make a fiery serpent and set it on a pole, and everyone who is bitten, when he sees it, shall live.” 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.