Revelation 3:4-5

3:4 But you have a few individuals in Sardis who have not stained their clothes, and they will walk with me dressed in white, because they are worthy. 3:5 The one who conquers will be dressed like them in white clothing, and I will never erase his name from the book of life, but will declare his name before my Father and before his angels.

Revelation 7:9

7:9 After these things I looked, and here was an enormous crowd that no one could count, made up of persons from every nation, tribe, people, and language, standing before the throne and before the Lamb dressed in long white robes, and with palm branches in their hands.

Revelation 7:14

7:14 So I said to him, “My lord, you know the answer.” Then he said to me, “These are the ones who have come out of the great tribulation. They have washed their robes and made them white in the blood of the Lamb!