Numbers 21:8-9 (NKJV)

8 "Then the LORD said to Moses, "Make a fiery serpent, and set it on a pole; and it shall be that everyone who is bitten, when he looks at it, shall live."
9 "So Moses made a bronze serpent, and put it on a pole; and so it was, if a serpent had bitten anyone, when he looked at the bronze serpent, he lived. "