John saw as an accomplished prophesy a unumberable crowd from all world history and every nation, tribe, tongue, peoples standing before the Lamb - the Redeemer Jesus Christ.
Do they all agree with me?
No. But they all agree that Jesus is Lord.
"And they cry with a loud voice,saying, Salvation to our God who sits upon the throne and to the Lamb."
They have all been operated upon by the Triune God, including God the Father and the Lamb of God - the Son.
The have gone through the process of BECOMING the city of God that expresses the union of divinity and humanity in the universe forever - New Jerusalem
They have passed through ALL of the tribulation of the entire epoch of the fallen universe under Satan's rebellion to be saved in God's faithful salvation. One of the 24 angelic elders explains this to the seer John.
"And one of the elders answered, saying to me, These who are clothed in white robes, who are they, and where did they come from?
And I said to him, My lord, you know. And he said to me, These are those who come out of the great tribulation, and they have washed their robes and made them white in the blood of the Lamb. (v.13,14)
The trillions of sins committed by all of them have been judged on the cross of the Redeemer - the Human Lamb of God Who died for the sins of the world. They have accepted Jesus as Lord.
They have come out of the entire world history before Christ and after Christ. Christ's sacrifice as the Lamb of God has not been limited to those only born after His incarnation.
conveys that God first passed over the sins before Christ's incarnation in anticipation of His coming. Then He came and the passed over sins were then taken completely away.
"[Christ] Whom God set forth as a propitiation place through faith in His blood, for the demonstrating of His righteousness, in that in His forbearance God passed over the sins that had previously occurred,
With a view to the demonstrating of His righteousness in the present time, so that He might be righteous and the One who justifies him who is of the faith of Jesus." (Rom. 5:25,26)
Everything about this I cannot explain. But the main point I make is that the great multitude comes out of the entire tribulation of human living in all ages upon the planet before the eternal age commences.
I used to think that Revelation 7:14
referred only to the last three and one half years of this age which is called "the great tribulation"
. I changed my mind one day and decided that here "come out of the great tribulation"
probably means the great tribulation in the universe since the rebellion of Satan - including all human history.
God is Jesus.