Let him sell his coat and buy a sword

I have always pondered on what was going on in Luke 22:36-38 when Christ told them His disciples to get swords and told them it was enough when they showed Him two.

But they said: Nothing. Then said he unto them: But now he that hath a purse, let him take it, and likewise a scrip; and he that hath not, let him sell his coat, and buy a sword. For I say to you, that this that is written must yet be fulfilled in me: And with the wicked was he reckoned. For the things concerning me have an end. But they said: Lord, behold here are two swords. And he said to them, It is enough.

I read a commentary once that said that Christ really meant the sword of the Spirit, but that explanation never really satisfied me. This morning I happened to read Unam Sanctam. I don't remember the series of events that led me to read it, but a passage in there dealt with this exact passage from Luke:

We are informed by the texts of the gospels that in this Church and in its power are two swords; namely, the spiritual and the temporal. For when the Apostles say: "Behold, here are two swords" [Lk 22:38] that is to say, in the Church, since the Apostles were speaking, the Lord did not reply that there were too many, but sufficient. Certainly the one who denies that the temporal sword is in the power of Peter has not listened well to the word of the Lord commanding: "Put up thy sword into thy scabbard" [Mt 26:52]. Both, therefore, are in the power of the Church, that is to say, the spiritual and the material sword, but the former is to be administered for the Church but the latter by the Church; the former in the hands of the priest; the latter by the hands of kings and soldiers, but at the will and sufferance of the priest. However, one sword ought to be subordinated to the other and temporal authority, subjected to spiritual power. For since the Apostle said: "There is no power except from God and the things that are, are ordained of God" [Rom 13:1-2], but they would not be ordained if one sword were not subordinated to the other and if the inferior one, as it were, were not led upwards by the other.

This explanation makes a lot more sense. Whenever the disciples didn't get what Christ was saying or bungled it He always reproved them, but in this case He didn't tell them they were wrong just that it was enough. Boniface VIII's explanation makes more sense to me, but I could be wrong and they could both be right and fit together in a way I am not able to see.

May God bless all who read my ramblings,