St. Thomas Aquinas, Supplement, Q. 19 “The Ministers of the Keys”, Art. 6, “Whether those who are schismatics, heretics, excommunicate, suspended or degraded have the use of the keys?”: “On the contrary, Augustine says (Tract. cxxi in Joan.) that the ‘charity of the Church forgives sins.’ Now it is the charity of the Church which unites its members. Since therefore the above are disunited from the Church, it seems that they have not the use of the keys... For since the use of the keys requires in the user authority over the person on whom they are used, as stated above (17, 2, ad 2), the proper matter on whom one can exercise the use of the keys is a man under one’s authority.”