Revelation 7:5-14

5 twelve thousand from each tribe: Judah, Reuben, Gad, Asher, Naphtali, Manasseh, Simeon, Levi, Issachar, Zebulun, Joseph, and Benjamin.
9 After this I looked, and there was an enormous crowd - no one could count all the people! They were from every race, tribe, nation, and language, and they stood in front of the throne and of the Lamb, dressed in white robes and holding palm branches in their hands. 1
10 They called out in a loud voice: "Salvation comes from our God, who sits on the throne, and from the Lamb!"
11 All the angels stood around the throne, the elders, and the four living creatures. Then they threw themselves face downward in front of the throne and worshiped God,
12 saying, "Amen! Praise, glory, wisdom, thanksgiving, honor, power, and might belong to our God forever and ever! Amen!"
13 One of the elders asked me, "Who are these people dressed in white robes, and where do they come from?"
14 "I don't know, sir. You do," I answered. 2 He said to me, "These are the people who have come safely through the terrible persecution. They have washed their robes and made them white with the blood of the Lamb.