Albert Barnes Commentary Revelation 5:10

"and madest them [to be] unto our God a kingdom and priests; and they reign upon earth." — Revelation 5:10 (ASV)

And have made us to our God kings and priests. (See Barnes on Revelation 1:6).

And we shall reign on the earth. This refers to the redeemed, of whom we are the representatives.

The idea clearly is, in accordance with what is so frequently said in the Scriptures, that the dominion on the earth will be given to the saints. That is, there will be such a prevalence of true religion, and the redeemed will be so much in the ascendancy, that the affairs of the nations will be in their hands.

Righteous men will hold the offices, fill places of trust and responsibility, and have a controlling voice in all that pertains to human affairs. (See Barnes on Daniel 7:27; see Barnes on Revelation 20:1 and following).

All things are tending toward such a prevalence of religion; and it is to this, in all the disorder and sin that now exist, that we are permitted to look forward.

It is not said that this will be a reign under the Saviour in a literal kingdom on the earth, nor is it said that the saints will descend from heaven, and occupy thrones of power under Christ as a visible king.

The simple affirmation is that they will reign on the earth. Since this seems to be spoken in the name of the redeemed, all that is necessary to understand is that true religion will prevail on the earth to such an extent that it will become a vast kingdom of holiness, and that, instead of being in the minority, the saints will everywhere have the ascendancy.