"The older I get, I wish Christians would be a little bit more like Jesus".

[Sibelius Fan]

9. Show me anywhere in the Bible where the idea is mentioned outside of Jesus saying it.

While you’re searching for a reply:

Jesus' Teachings on Fiery Punishment
Gehenna (Valley of Hinnom): Jesus frequently spoke of Gehenna, a physical valley outside Jerusalem used as a garbage dump where fires burned constantly, as a symbol of eternal destruction, a place where the "maggot does not die and the fire is not put out" (Matthew 23:33, Mark 9:47-48).
Matthew 25:41: In the parable of the sheep and goats, Jesus describes the wicked going "away to eternal punishment, into everlasting fire, prepared for the devil and his angels".
Matthew 13:42 & 18:8: He speaks of a fiery furnace where people will be cast, a place of weeping and gnashing of teeth.
Matthew 10:28: He warns against fearing those who can kill the body but rather fearing Him who can "destroy both soul and body in hell" (Gehenna).

In Mark 16:16, Jesus says you must believe in him and be baptized to have eternal life, otherwise, god will condemn you and punish you in hell.