Would you please, using even a Catholic Bible, give us references as to where such a concept comes from?
There’s no ‘Catholic bible’. There just the Bible.
There are two passages which refer to Confession of Sins.
Christ says to Peter, whatcosver you bind on earth shall be bound in heaved, and whatsoever you shall loose on earth, shall be loosed on heaven.
As the priests are the successors of the Apostles, they also hold this authority.
‘As the Father hath sent me, I also send you. When he had said this, he breathed on them; and he said to them: Receive ye the Holy Ghost. Whose sins you shall forgive, they are forgiven them; and whose sins you shall retain, they are retained.’
This is why priests can hold confessions, and can absolve, by the Power of Christ in them.