Pope Pius XII
Mystici Corporis Christi §54
Mystici Corporis Christi: On the Mystical Body of Christ
54 Nevertheless this most noble title of the Church must not be so understood as if that ineffable bond by which the Son of God assumed a definite human nature belongs to the universal Church; but it consists in this, that our Savior shares prerogatives peculiarly His own with the Church in such a way that she may portray, in her whole life, both exterior and interior, a most faithful image of Christ. For in virtue of the juridical mission by which our Divine Redeemer sent His Apostles into the world, as He had been sent by the Father, it is He who through the Church baptizes, teaches, rules, looses, binds, offers, sacrifices.
Source: Mystici Corporis Christi (Vatican.va)