Philippians 2:10-11
that at the name of Jesus every knee should bow, of those in heaven, and of those on earth, and of those under the earth, and that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father.
Revelation 5:13
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, “To him who sits on the throne and to the Lamb be blessing and honor and glory and might forever and ever!”
Universalists often cite these texts as saying every creature that has ever lived will be saved. But “under the earth” most likely is a reference to purgatory. Augustine believed hell and purgatory were in the same location they are just different states of being. This has been confirmed by the holy saints and mystics visions of both hell and purgatory and would explain why the gates of the heavenly city remain open. It’s for those in purgatory. The church in heaven, the church on earth and the church under the earth (purgatory) all sing glory and might to God forever and ever! Those in the state of hell hate God and have no love for Him. This is also why the rich man who begged for mercy because of his torments was in purgatory and not eternal punishment. He still had love in his heart.