Why forgiveness is so important and paramount to a healthy communication? How to attain God’s Peace?

John 20:21-23 KJV

[21] Then said Jesus to them again, Peace be unto you: as my Father hath sent me, even so send I you. [22] And when he had said this, he breathed on them, and saith unto them, Receive ye the Holy Ghost: [23] Whose soever sins ye remit, they are remitted unto them; and whose soever sins ye retain, they are retained.

If you remit the sins of any persons, they remain remitted to them. If you bind fast the sins of any, they remain bound."