Revelation 7:13-14 NKJV
Then one of the elders answered, saying to me, “Who are these arrayed in white robes, and where did they come from?”
And I said to him, “Sir, you know.”
So he said to me, “These are the ones who come out of the great tribulation, and washed their robes and made them white in the blood of the Lamb.
NKJV: New King James Version