John 20:23

Any to whom you give forgiveness, will be made free from their sins; and any from whom you keep back forgiveness, will still be in their sins.

Matthew 16:19

I will give to you the keys of the kingdom of heaven: and whatever is fixed by you on earth will be fixed in heaven: and whatever you make free on earth will be made free in heaven.

Matthew 18:18

Truly I say to you, Whatever things are fixed by you on earth will be fixed in heaven: and whatever you make free on earth will be made free in heaven.

Mark 2:5-10

And Jesus, seeing their faith, said to him, Son, you have forgiveness for your sins.

1 Corinthians 5:4

In the name of our Lord Jesus, when you have come together with my spirit, with the power of our Lord Jesus,

Acts 2:38

And Peter said, Let your hearts be changed, every one of you, and have baptism in the name of Jesus Christ, for the forgiveness of your sins; and you will have the Holy Spirit given to you.

Acts 10:43

To him all the prophets give witness, that through his name everyone who has faith in him will have forgiveness of sins.

Acts 13:38-39

And so, let it be clear to you, my brothers, that through this man forgiveness of sins is offered to you:

2 Corinthians 2:6-10

Let it be enough for such a man to have undergone the punishment which the church put on him;

Ephesians 2:20

Resting on the base of the Apostles and prophets, Christ Jesus himself being the chief keystone,

1 Timothy 1:20

Such are Hymenaeus and Alexander, whom I have given up to Satan, so that they may say no more evil words against God.

Treasury of Scripture Knowledge

Summary

Whose soever sins ye remit, they are remitted unto them; and whose soever sins ye retain, they are retained.

Bible References

General references

Matthew 16:19
I will give to you the keys of the kingdom of heaven: and whatever is fixed by you on earth will be fixed in heaven: and whatever you make free on earth will be made free in heaven.
Matthew 18:18
Truly I say to you, Whatever things are fixed by you on earth will be fixed in heaven: and whatever you make free on earth will be made free in heaven.
Mark 2:5
And Jesus, seeing their faith, said to him, Son, you have forgiveness for your sins.
Acts 2:38
And Peter said, Let your hearts be changed, every one of you, and have baptism in the name of Jesus Christ, for the forgiveness of your sins; and you will have the Holy Spirit given to you.
Acts 10:43
To him all the prophets give witness, that through his name everyone who has faith in him will have forgiveness of sins.
Acts 13:38
And so, let it be clear to you, my brothers, that through this man forgiveness of sins is offered to you:
1 Corinthians 5:4
In the name of our Lord Jesus, when you have come together with my spirit, with the power of our Lord Jesus,
2 Corinthians 2:6
Let it be enough for such a man to have undergone the punishment which the church put on him;
Ephesians 2:20
Resting on the base of the Apostles and prophets, Christ Jesus himself being the chief keystone,
1 Timothy 1:20
Such are Hymenaeus and Alexander, whom I have given up to Satan, so that they may say no more evil words against God.

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain