Revelation 7:13-15

Then one of the elders asked me, “Who are these in glistening white robes, and where have they come from?” I answered, “My lord—you must know.” Then he said to me, “They are ones who have washed their robes and made them white in the blood of the Lamb and have emerged from the midst of great pressure and ordeal. For this reason they are before the throne of God, ministering to him as priests day and night, within his cloud-filled sanctuary. And the enthroned One spreads over them his tabernacle-shelter.