Numbers 21:6

3 And the LORD hearkened to the voice of Israel, and delivered up the Canaanites; and they utterly destroyed them and their cities: and he called the name of the place Hormah.

4 And they journeyed from mount Hor by the way of the Red sea, to compass the land of Edom: and the soul of the people was much discouraged because of the way.

5 And the people spoke against God, and against Moses, Why have ye brought us out of Egypt to die in the wilderness? for [there is] no bread, neither [is there any] water; and our soul lotheth this light bread.

6 And the LORD sent fiery serpents among the people, and they bit the people; and many people of Israel died.

7 Therefore the people came to Moses, and said, We have sinned, for we have spoken against the LORD, and against thee; pray to the LORD, that he take away the serpents from us. And Moses prayed for the people.

8 And the LORD said to Moses, Make thee a fiery serpent, and set it upon a pole: and it shall come to pass, that every one that is bitten, when he looketh upon it, shall live.

9 And Moses made a serpent of brass, and put it upon a pole, and it came to pass, that if a serpent had bitten any man, when he beheld the serpent of brass, he lived.