Hence, “the gates of Hades” must remain closed upon such ones and upon all the other ransomed human dead until the establishment of Christ’s kingdom in the heavens at God’s appointed time.​—Matt. 16:18; Isa. 38:10, 18.

So, when the last one of the ransomed human dead has been called forth through the opened “gates of Hades,” the common grave of mankind will exist no more. Hades will have been cast into the “lake of fire,” to its own eternal death.