Numbers 21:8 - 9
ESV - 8 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. 9 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.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.