In Revelation chapter 5 verses 9-10 we are presented with a group of blood bought, resurrected and raptured saints.
We know they have already been raised/caught up because we see them in Heaven, before the throne of God wearing crowns of gold (Revelation 4:4). They have already been raised, judged and rewarded.
The chronology of The Revelation is clear that these things occur before any seals of judgment are opened and loosed on the earth initiating The Beginning of Sorrows and The Great Tribulation.
These redeemed people are praising the Lamb for two things. They are praising him for redeeming them with his blood, and they are praising him because they are looking forward to reigning on the earth with him.
Jesus, the only Christ, is God of gods, Lord of lords, and King of kings. And he will have the last word. He that sits in the Heavens shall laugh. The Lord shall have his enemies in derision, and Jesus will establish a kingdom that will have no end. But he is not reigning on this earth just yet. With all the filth and unrighteousness we see around us, it is a gross insult to him to even suggest that he is. It goes without speaking that those who belong to him are not reigning yet either, nor will they until Heaven opens and Christ returns visibly and physically to this earth with all his saints.
Those who teach that mere mortal men will be instrumental in “ushering in” the Kingdom of Christ by bringing about conditions on earth which will “release” Christ from Heaven are liars. If they do not repent, they will find themselves turned over to the lie and being thrown into the lake of fire. If those who follow them do not repent, they are in serious danger of sharing that same fate (2 Thessalonians 2:11-12kjv).
In Revelation 5:9-10 we see two things quite clearly. We see the pre-tribulational resurrection of the dead in Christ and the pre-tribulational rapture of the ekklesia—the called out [out of] assembly (i.e., the Church). We also see that any ruling and reigning that will be done, is still a future event and will not take place until after The Great Tribulation is concluded. We know this because Christ will not return to earth with his resurrected and raptured saints until the battle of Armageddon concludes The Time of Jacob’s Trouble (Revelation 19).