Those whose sins you shall forgive, they are forgiven them, and those whose sins you shall retain, they are retained.
Other versions
King James Version
Whose soever sins ye remit, they are remitted unto them; and whose soever sins ye retain, they are retained.English Standard Version
If you forgive the sins of anyone, they are forgiven; if you withhold forgiveness from anyone, it is withheld."New International Version
If you forgive anyone his sins, they are forgiven; if you do not forgive them, they are not forgiven."