Randy Alcorn, who wrote a fantastic book on Heaven made 21 observations about Revelation 6:9-11, giving us some insight about what the saints in Heaven are experiencing right now!
1. When these people died on Earth, they relocated to Heaven (v.9).
2. These people in Heaven were the same ones killed for Christ while on Earth (v. 9). This demonstrates direct continuity between our identity on Earth and our identity in Heaven. The martyrs' personal history extends directly back to their lives on Earth. Those in the intermediate Heaven are not different people; they are the same people relocated—"righteous men made perfect" (Hebrews 12:23).
3. People in Heaven will be remembered for their lives on Earth. These were known and identified as ones slain "because of…the testimony they had maintained" (v. 9).
4. "They called out" (v. 10) means they are able to express themselves audibly. This could suggest they exist in physical form, with vocal cords or other tangible means to express themselves.
5. People in the intermediate Heaven can raise their voices (v. 10). This indicates that they are rational, communicative, and emotional—even passionate—beings, like people on Earth.
6. They called out in "a loud voice," not "loud voices." Individuals speaking with one voice indicate that Heaven is a place of unity and shared perspective.
7. The martyrs are fully conscious, rational, and aware of each other, God, and the situation on Earth.
8. They ask God to intervene on Earth and to act on their behalf: "How long…until you judge the inhabitants of the earth and avenge our blood?"(v. 10).
9. Those in Heaven are free to ask God questions, which means they have an audience with God. It also means they need to learn. In Heaven, people desire understanding and pursue it.
10. People in the intermediate Heaven know what's happening on Earth (v. 10). The martyrs know enough to realize that those who killed them have not yet been judged.
11. Heaven dwellers have a deep concern for justice and retribution (v. 10). When we go to Heaven, we won't adopt a passive disinterest in what happens on the earth. On the contrary, our concerns will be more passionate and our thirst for justice greater. Neither God nor we will be satisfied until his enemies are judged, our bodies raised, sin and Satan defeated, Earth restored, and Christ exalted over all.
12. The martyrs clearly remember their lives on Earth (v. 10). They remember at least some of the bad things from earth, since they even remember that they were murdered. (Heaven's joys are not rooted in ignorance, but perspective.) - PLEASE LET THAT SINK IN.
13. The martyrs in Heaven pray for judgment on their persecutors who are still at work hurting others. They are acting in solidarity with, and in effect interceding for, the suffering saints on Earth. This suggests that saints in Heaven are both seeing and praying for saints on Earth.
14. Those in Heaven see God's attributes ("Sovereign…holy and true") in a way that makes his judgment of sin more understandable.
15. Those in Heaven are distinct individuals: "Then each of them was given a white robe" (v. 11). There isn't one merged identity (ala Nirvana) that obliterates uniqueness, but a distinct "each of them."
16. The martyrs' wearing white robes suggests the possibility of actual physical forms, because disembodied spirits presumably don't wear robes. The robes may well have symbolic meaning, but it doesn't mean they couldn't also be physical. The martyrs appear to have physical forms that John could actually see.
17. God answers their question (v. 11), indicating communication and process in Heaven. It also demonstrates that we won't know everything in Heaven—if we did, we would have no questions. The martyrs knew more after God answered their question than before they asked it. There is learning in the present Heaven.
18. God promises to fulfill the martyrs' requests, but says they will have to "wait a little longer" (v. 11). Those in the intermediate Heaven live in anticipation of the future fulfillment of God's promises. Unlike the eternal Heaven—where there will be no more sin, Curse, or suffering on the New Earth (Revelation 21:4)—the present Heaven coexists with and watches over an Earth under sin, the Curse, and suffering.
19. There is time in the intermediate Heaven (vv. 10-11). The white-robed martyrs ask God a time-dependent question: "How long, Sovereign Lord…until you judge the inhabitants of the earth and avenge our blood?" (v. 10). They are aware of time's passing and are eager for the coming day of the Lord's judgment. God answers that they must "wait a little longer" until certain events transpire on Earth. Waiting requires the passing of time. (This seems to refute the "no time in Heaven/ instantaneous resurrection" theory, as well as soul sleep.)
20. The people of God in Heaven have a strong familial connection with those on Earth, who are called their "fellow servants and brothers" (v. 11). We share the same Father, "from whom every family in heaven and on earth is named" (Ephesians 3:15, ESV). There is not a wall of separation within the bride of Christ. We are one family with those who've gone to Heaven ahead of us. After we go to Heaven, we'll still be one family with those yet on Earth. These verses demonstrate a vital connection between the events and people in Heaven and the events and people on Earth.
21. Our sovereign God knows down to the last detail all that is happening and will happen on Earth (v. 11), including every drop of blood shed and every bit of suffering undergone by his children. Voice of the Martyrs estimates that more than 150,000 people die for Christ each year, an average of more than four hundred per day. God knows the name and story of each one. He knows exactly how many martyrs there will be, and he is prepared to return and set up his Kingdom when the final martyr dies.