All men will die.
All men that die will be in their grave.
Hell means grave.
Some will be in their grave sleeping, waiting for the return of Jesus.
Many will be dead in their grave, and will be dead forever.
Matthew 7:13-14 KJV
[13] Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat: [14] Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.
There are entrance requirements to heaven.
To enter the dead forever grave, do not do the requirements to enter heaven.
Matthew 8:22 KJV
[22] But Jesus said unto him, Follow me; and let the dead bury their dead.
Matthew 9:24-25 KJV
[24] He said unto them, Give place: for the maid is not dead, but sleepeth. And they laughed him to scorn. [25] But when the people were put forth, he went in, and took her by the hand, and the maid arose.
John 3:36 KJV
[36] He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him.
Entrance requirements to be dead forever, is to refuse to do the entrance requirements to heaven.
To have everlasting life, review here the entrance requirements for heaven:
Entrance requirements to heaven, 1.4.17.0