Numbers 21:5-9

5and the people spoke against 1God, and against Moses, Why have ye brought us up out of Egypt that we should die in the wilderness? for there is no bread, and no water, and our soul loathes this light bread.

6Then Jehovah sent fiery serpents among the people, which bit the people; and much people of Israel died.

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

8And Jehovah 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, and looketh upon it, shall live.

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