Revelation 7:14

I said to him, "Sir, you know." And he said to me, "These are they who have come out of the great tribulation; they have washed their robes and made them white in the blood of the Lamb.

1 John 1:7

But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin.

Hebrews 9:14

how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, cleanse your conscience from dead works to serve the living God?

Revelation 1:5

and from Jesus Christ, who is the faithful witness, the firstborn from the dead, and the ruler of the kings of the earth. To him who loves us and has freed us from our sins by his blood,

Revelation 22:14

Blessed are those who wash their robes, so that they may have the right to the tree of life, and may enter by the gates into the city.

Matthew 24:21

For then there will be great tribulation, such as has not been from the beginning of the world until now, no, and never will be.

John 13:8-14

Peter said to him, "You shall never wash my feet." Jesus answered him, "If I do not wash you, you have no part with me."

John 16:33

I have said these things to you, that in me you may have peace. In the world you will have tribulation. But take courage! I have overcome the world."

Acts 14:22

strengthening the souls of the disciples, encouraging them to continue in the faith, and saying, "Through many tribulations we must enter the kingdom of God."

Romans 5:3

And not only that, but we rejoice in our sufferings, knowing that suffering produces perseverance;

1 Corinthians 6:11

And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and in the Spirit of our God.

Ephesians 5:26-27

that he might sanctify her, having cleansed her by the washing of water with the word,

2 Thessalonians 1:4

Therefore we ourselves boast of you among the churches of God for your perseverance and faith in all your persecutions and in the afflictions which you are enduring.

Hebrews 13:12

And so Jesus also suffered outside the city gate to sanctify the people through his own blood.

1 Peter 1:19

but with the precious blood of Christ, like that of a lamb without blemish or spot.

Revelation 2:9

I know your tribulation and your poverty (but you are rich) and I know the slander of those who say that they are Jews and are not, but are a synagogue of Satan.

Revelation 5:9

And they sang a new song, saying, "Worthy are you to take the scroll and to open its seals; for you were slain, and with your blood purchased men for God from every tribe and tongue and people and nation.

Revelation 6:9-11

When he opened the fifth seal, I saw under the altar the souls of those who had been slain because of the word of God and the testimony they had maintained;

Revelation 12:11

They overcame him by the blood of the Lamb and by the word of their testimony, and they did not love their lives even to the death.

Revelation 15:2

And I saw what looked like a sea of glass mixed with fire and, standing beside the sea of glass, those who had been victorious over the beast and his image and over the number of his name. They held harps of God

Revelation 17:6

And I saw the woman drunk with the blood of the saints, and with the blood of the witnesses of Jesus. When I saw her, I wondered greatly.

Treasury of Scripture Knowledge

Summary

And I said unto him, Sir, thou knowest. And he said to me, These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb.

General references

Bible References

And have

Revelation 1:5
and from Jesus Christ, who is the faithful witness, the firstborn from the dead, and the ruler of the kings of the earth. To him who loves us and has freed us from our sins by his blood,
John 13:8
Peter said to him, "You shall never wash my feet." Jesus answered him, "If I do not wash you, you have no part with me."
1 Corinthians 6:11
And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus Christ and in the Spirit of our God.
Ephesians 5:26
that he might sanctify her, having cleansed her by the washing of water with the word,
Hebrews 9:14
how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, cleanse your conscience from dead works to serve the living God?
1 John 1:7
But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin.

The blood

Revelation 5:9
And they sang a new song, saying, "Worthy are you to take the scroll and to open its seals; for you were slain, and with your blood purchased men for God from every tribe and tongue and people and nation.
Revelation 12:11
They overcame him by the blood of the Lamb and by the word of their testimony, and they did not love their lives even to the death.
Hebrews 13:12
And so Jesus also suffered outside the city gate to sanctify the people through his own blood.
1 Peter 1:19
but with the precious blood of Christ, like that of a lamb without blemish or spot.

General references

Matthew 5:4
Blessed are those who mourn, for they shall be comforted.