The power of the keys is that power given by our Blessed Lord to his Church (through Peter and other Apostles) in order to continue his works of salvation. It is the power to bind and loose. In simple words, it is the power to forgive sins. (Ref Matt 16 :19). Based on this power bestowed upon the apostles (as representatives of Christ), by the virtue of their priesthood, I wish to make certain comparative analysis that can only be comprehensible by Faith rather than reason.
One of the thought provoking expression I read from Alphonsus Liguori is: “All the angels in heaven cannot absolve from a single sin”. St. Gregory Nazianzen seem to have known this truth when he stated that the sacerdotal dignity surpasses the dignity of the angels, who likewise show their veneration for the priesthood. However, our guardian angels have a special role to play on the absolution of sin. This is because they procure for the souls committed to their care grace to have recourse to a priest that he may absolve them: “Although,” says St. Peter Damian, “angels may be present, they yet wait for the priest to exercise his power, but no one of them has the power of the keys – of binding and of loosening.”
Could this be surprising? Certainly not. This is predicated on the fact that Our Blessed Lord himself, in order to absolve the sins of the world, preferred to take human nature. Hence in theology, we can talk of hypostatic union (that is two natures in one person). Meanwhile, unlike angels, He (Christ) knew what it means to be human, and so was able to sympathize with us. In the same way, those whom he called to be priests are composite beings (they possess body and soul). The words in Hebrew perfectly captured this when the author says “every high priest is taken from among men and appointed to be their representative before God…. He is able to understand the ignorant and erring for he himself is subject to weakness. That is why he is bound to offer sacrifices for his sins as well as for the sins of the people. Besides one does not take this honor upon himself, but takes it only when called by God as Aaron was. (5:1-4).
For more clarification, it could be faithfully observed that when St. Michael comes to a dying Christian who invokes his aid, the holy archangel can chase away the devils, but he cannot free his client from their chains till a priest comes to absolve him. After having given the order of priesthood to a holy ecclesiastic, St. Francis de Sales perceived, that in going out he stopped at the door as if to give precedence to another. Being asked by the saint why he stopped, he answered that God favoured him with the visible presence of his angel guardian, who before he had received priesthood always remained at his right and preceded him, but afterwards walked on his left and refused to go before him. It was in a holy contest with the angel that he stopped at the door.
Priesthood is an awesome gift from God that should be guided in a dignified manner. May God continue to sustain and strengthen us with his grace and mercy for the ministry.