The children of Israel repeatedly grumbled against God and Moses. God responded by sending “fiery serpents” among them (Num. 21:6), probably poisonous vipers whose bites caused intense fever, thirst, swelling, and eventually death.
And the LORD sent fiery serpents among the people, and they bit the people; and much people of Israel died.
Therefore the people came to Moses, and said, We have sinned, for we have spoken against the LORD, and against thee; pray unto the LORD, that he take away the serpents from us. And Moses prayed for the people.
And the LORD said unto 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.
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.
The snakes may also have been “fiery” in terms of their appearance. One very poisonous species in the region has brightly colored red spots and wavy stripes, and is greatly feared by the Arabs even today.
The Israelites acknowledged their sin and cried out for mercy and deliverance (Num. 21:7). In response, the LORD told Moses to fashion a fiery serpent on a pole, which would provide a means of healing (Num. 21:8).
A bronze serpent was cast, which would have given off a fiery appearance in the sunlight, making a highly visible standard for the people to see.
All that they had to do, in order to live, was look at the Brazen Serpent. And they lived.
Jesus refers to the bronze serpent in his conversation with Nicodemus.
The Lord said that He would have to be “lifted up” just as the bronze serpent was in order to bring eternal life to those who believe in Him. (John 3:14,15)