"Therefore God exalted Him to the highest place and gave Him the name above all names, that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.
"And I heard every creature in heaven and on earth and under the earth and in the sea, and all that is in them, saying:"
"But no one in heaven or on earth or under the earth was able to open the scroll or look inside it.
All those 'under the earth' is in reference to those spirits who died in their sins, who are in Hades and who are conscious and aware.
"And when the Lamb opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the testimony they had upheld. And they cried out in a loud voice, “How long, O Lord, holy and true, until You avenge our blood and judge those who dwell upon the earth?”
ECC 9:5 For the living know that they shall die: but the dead know not any thing, neither have they any more a reward; for the memory of them is forgotten.
9:6 Also their love, and their hatred, and their envy, is now perished; neither have they any more a portion for ever in any [thing] that is done under the sun.
Then each of them was given a white robe and told to rest a little while longer, until the full number of their fellow servants, their brothers, were killed, just as they had been killed.
PAUL AND DAVID ARE IN THE GRAVES TILL YESUAH COMES AND RESURECTS THEM, IT EVEN TELLS YOU THAT DAVID THE KING HAS NOT ASCENDED TO HEAVEN, IN THE NEW TESTAMENT AFTER HE HAD BEEN DEAD FOR MANY MANY YEARS, HE is in HIS GRAVE LIKE PAUL AND THE REST OF US WHEN WE DIE.
These under the altar in heaven are the spirits of the righteous who are conscious and aware having a conversation with the Lord.