But can you prove that God did delegate that power to men?

The Catholic Answers

Yes. Christ was God, and in St. Jn. XX., 21-23 we read these remarkable words, “As the Father hath sent Me I also send you. When He 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.” Now Christ’s mission was to destroy sin, and He gave that same mission to His Apostles. Knowing that their merely human power as men was quite insufficient, He gave them a special communication of the Holy Spirit for this special work. To say that Christ did not confer a true power to forgive sin is to rob the whole ceremony and the words of Christ of any real meaning. And it was obviously a power to be exercised, Christians applying to the Apostles for forgiveness.

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty