Matthew 18:18

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.

Cross-references

Matthew 16:19 gives Peter the same binding/loosing authority that Jesus here extends to all disciples — identical teaching.

John 20:23 Parallel

John 20:23 parallels binding/loosing with forgiving/retaining sins — both grant apostolic authority over forgiveness.

2 Corinthians 2:10 demonstrates apostolic forgiveness, corresponding to the 'loosing' aspect of binding and loosing in Matthew 18:18.

Isaiah 22:22 describes the key of David with opening and shutting authority — a clear type of the binding and loosing power given to disciples.

John 9:34 Contrast

John 9:34 shows the Pharisees wrongly excommunicating a man — contrasting the legitimate binding authority given to the church.