Matthew 18:18

I assure you and most solemnly say to you, whatever you bind [forbid, declare to be improper and unlawful] on earth shall have [already] been bound in heaven, and whatever you loose [permit, declare lawful] on earth shall have [already] been loosed in heaven.

Matthew 16:19

I will give you the keys (authority) of the kingdom of heaven; and whatever you bind [forbid, declare to be improper and unlawful] on earth will have [already] been bound in heaven, and whatever you loose [permit, declare lawful] on earth will have [already] been loosed in heaven.”

John 20:23

If you forgive the sins of anyone they are forgiven [because of their faith]; if you retain the sins of anyone, they are retained [and remain unforgiven because of their unbelief].”

2 Corinthians 2:10

If you forgive anyone anything, I too forgive [that one]; and what I have forgiven, if I have forgiven anything, has been for your sake in the presence of [and with the approval of] Christ,

Revelation 3:7-8

“And to the angel (divine messenger) of the church in Philadelphia write:

“These are the words of the Holy One, the True One, He who has the key [to the house] of David, He who opens and no one will [be able to] shut, and He who shuts and no one opens:

Acts 15:23-31

With them they sent the following letter:

“The apostles and the brothers who are the elders, to the brothers and sisters who are from the Gentiles in Antioch, Syria, and Cilicia, Greetings.

1 Corinthians 5:4-5

In the name of our Lord Jesus, when you are assembled, and I am with you in spirit, with the power of our Lord Jesus,

Treasury of Scripture Knowledge

Summary

Verily I say unto you, Whatsoever ye shall bind on earth shall be bound in heaven: and whatsoever ye shall loose on earth shall be loosed in heaven.

Bible References

General references

Matthew 16:19
I will give you the keys (authority) of the kingdom of heaven; and whatever you bind [forbid, declare to be improper and unlawful] on earth will have [already] been bound in heaven, and whatever you loose [permit, declare lawful] on earth will have [already] been loosed in heaven.”
John 20:23
If you forgive the sins of anyone they are forgiven [because of their faith]; if you retain the sins of anyone, they are retained [and remain unforgiven because of their unbelief].”
Acts 15:23
With them they sent the following letter:

“The apostles and the brothers who are the elders, to the brothers and sisters who are from the Gentiles in Antioch, Syria, and Cilicia, Greetings.
1 Corinthians 5:4
In the name of our Lord Jesus, when you are assembled, and I am with you in spirit, with the power of our Lord Jesus,
2 Corinthians 2:10
If you forgive anyone anything, I too forgive [that one]; and what I have forgiven, if I have forgiven anything, has been for your sake in the presence of [and with the approval of] Christ,
Revelation 3:7
“And to the angel (divine messenger) of the church in Philadelphia write:

“These are the words of the Holy One, the True One, He who has the key [to the house] of David, He who opens and no one will [be able to] shut, and He who shuts and no one opens: