"After this I looked and there before me was a great multitude that no one could count, from every nation, tribe, people and language, standing before the throne and in front of the Lamb. They were wearing white robes and were holding palm branches
in their hands. And they cried out in a loud voice: "Salvation belongs to our God, who sits on the throne, and to the Lamb." All the angels were standing around the throne

……(v13) Then one of the elders asked me, "These in white robes – who are they and where did they come from?" And he said, these are those who have come out of the great tribulation; they have washed their robes and made them white in the blood of the Lamb. Therefore, " they are before the throne of God……""