Numbers 21:4-9

4 From Mount Hor they set out on the Red Sea road, to by-pass the land of Edom. But with their patience worn out by the journey, 5 the people complained against God and Moses, "Why have you brought us up from Egypt to die in this desert, where there is no food or water? We are disgusted with this wretched food!"

6 In punishment the LORD sent among the people saraph serpents, which bit the people so that many of them died.

7 Then the people came to Moses and said, "We have sinned in complaining against the LORD and you. Pray the LORD to take the serpents from us." So Moses prayed for the people,

8 and the LORD said to Moses, "Make a saraph and mount it on a pole, and if anyone who has been bitten looks at it, he will recover."

9 Moses accordingly made a bronze serpent and mounted it on a pole, and whenever anyone who had been bitten by a serpent looked at the bronze serpent, he recovered.