Revelation 7:13-15

Then one of the elders asked me, “Who are these people dressed in white robes? Where did they come from?” I answered, “You know, sir.” And the elder said to me, “These are the people who have come out of the great distress. They have washed their robes and made them white in the blood of the Lamb. Because of this, they are before the throne of God. They worship him day and night in his temple. And the One who sits on the throne will be present with them.