Which hell? Sheol, Gehenna or Hades? If you refer to Mark 9:43-48, you will see he quoted the last Verse of Isaiah 66.
Yet, the Lake of Fire is a very different place. Plus, I see many Verses in the Old Testament that seem to state that the dead are unconcious until they will be resurrected and judged. I could be wrong, but I can see a lot of evidence.
When I say Sheol/Hades both being the same place, I'm referring to the place of torment under the earth. Gehenna is another designation for the lake of fire whose location is not given, but is most likely not on the earth.
Brother, where are you getting your information from? What you are referring to is the belief in soul sleep, which also false. Consider the following:
"Therefore we are always confident, although we know that while we are at home in the body, we are away from the Lord. For we walk by faith, not by sight. We are confident, then, and would prefer to be away from the body and at home with the Lord."
"For to me, to live is Christ, and to die is gain. But if I go on living in the body, this will mean fruitful labor for me. So what shall I choose? I do not know. I am torn between the two. I desire to depart and be with Christ, which is far better indeed. But it is more necessary for you that I remain in the body."
In both scriptures above, Paul is referring the death of the body. Once a believer dies their spirit departs and goes to be in the presence of the Lord where they look forward to the resurrection while their spirits are in heaven. Even when Stephan was being stoned he said, "Lord, receive my spirit."
We have another of conscious awareness of the spirits after death at the opening of the 5th seal where we see the souls of those under the altar in heaven having a conversation with the Lord and who are given white robes to wear.
We also have the information regarding the rich man and Lazarus which shows two men who died, yet their spirits went somewhere else. Lazarus' spirit went to the place of comfort/paradise in Sheol/Hades, where the rich man was in another location within sheol/hades in torment in flame. Both locations were separated by a great chasm (See Luke 16:19). This demonstrates that both of their spirits were conscious and aware after the death of their bodies. The teaching that the rich man and Lazarus as being a parable is how many have attempted to get rid of the truths contained within this information. God's word seems to be under attack on every level.