Whether the key is the power of binding and loosing, etc.?

❌ Objection 1 : It would seem that the key is not the power of binding and loosing, whereby "the ecclesiastical judge has to admit the worthy to the kingdom and exclude the unworthy" therefrom, as stated in the text (Sent. iv, D, 16). For the spiritual power conferred in a sacrament is the same as the character. But the key and the character do not seem to be the same, since by the character man is referred to God, whereas by the key he is referred to his subjects. Therefore the key is not a power.

❌ Objection 2 : Further, an ecclesiastical judge is only one who has jurisdiction, which is not given at the same time as orders. But the keys are given in the conferring of orders. Therefore there should have been no mention of the ecclesiastical judge in the definition of the keys.

❌ Objection 3 : Further, when a man has something of himself, he needs not to be reduced to act by some active power. Now a man is admitted to the kingdom from the very fact that he is worthy. Therefore it does not concern the power of the keys to admit the worthy to the kingdom.

❌ Objection 4 : Further, sinners are unworthy of the kingdom. But the Church prays for sinners, that they may go to heaven. Therefore she does not exclude the unworthy, but admits them, so far as she is concerned.

❌ Objection 5 : Further, in every ordered series of agents, the last end belongs to the principal and not to the instrumental agent. But the principal agent in view of man's salvation is God. Therefore admission to the kingdom, which is the last end, belongs to Him, and not to those who have the keys, who are as instrumental or ministerial agents.