As someone raised in a very Fundamentalist Christian denomination that preached more about Hell fire than Heaven, and more wrath of God than love and compassion of God, I was always curious why such a terrible place was not mentioned in the Old Testament.
Actually, there are references to it, but they are not as blatantly stated as they were by Jesus.
If the purpose of your OP is to prove there is no feiry hell, then all of the verses from the OT won't matter to you. If you refuse to accept the words of Jesus, why would you believe anything the OT has to say?
Here is just one example. I can post more if you are truly seeking to learn.
Isaiah 66:24
22 “As the new heavens and the new earth that I make will endure before me,” declares the Lord, “so will your name and descendants endure.
23 From one New Moon to another and from one Sabbath to another, all mankind will come and bow down before me,” says the Lord.
24 “And they will go out and look on the dead bodies of those who rebelled against me; the
worms that eat them will not die, the fire that burns them will not be quenched, and they will be loathsome to all mankind.”