[Num 21:9 KJV] 9 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.
Of course context matters but most would not have understood fiery
[Num 21:8 KJV] 8 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.
[Isa 54:17 KJV] 17 No weapon that is formed against thee shall prosper; and every tongue [that] shall rise against thee in judgment thou shalt condemn. This [is] the heritage of the servants of the LORD, and their righteousness [is] of me, saith the LORD.