Poison

the text before the famous John 3:16 verse is all about the Son of Man being lifted up like the bronze serpent

the serpent bite caused the venom to flow through Adam's veins

Christ takes the poison in the flesh into His own flesh and instead brings the new Spirit that has the new life blood - coming from the heart of Christ (which is the new heart)

but what is the poison?
it is the lie that God is a slave-driver, God is wicked, God holds back from you, God hates you...
He is not a good Father

then re-read John 3:16 - listen to Jesus slowly and carefully:

For God SO LOVED the world, that He gave His only begotten Son...

Keep looking to Jesus.. take out the poison...