Unam Sanctam interpretation I already gave. But I will give much, much older document that I already mentioned, Famuli vestrae pietatis or as it's commonly named, Duo Sunt.
There are two powers, august Emperor, by which this world is chiefly ruled, namely, the sacred authority of the priests and the royal power. Of these, that of the priests is the more weighty, since they have to render an account for even the kings of men in the divine judgment. You are also aware, dear son, that while you are permitted honorably to rule over human kind, yet in things divine you bow your head humbly before the leaders of the clergy and await from their hands the means of your salvation. In the reception and proper disposition of the heavenly mysteries you recognize that you should be subordinate rather than superior to the religious order, and that in these matters you depend on their judgment rather than wish to force them to follow your will.
If the ministers of religion, recognizing the supremacy granted you from heaven in matters affecting the public order, obey your laws, lest otherwise they might obstruct the course of secular affairs by irrelevant considerations, with what readiness should you not yield them obedience to whom is assigned the dispensing of the sacred mysteries of religion. Accordingly, just as there is no slight danger in the case of the priests if they refrain from speaking when the service of the divinity requires, so there is no little risk for those who disdain–which God forbid–when they should obey. And if it is fitting that the hearts of the faithful should submit to all priests in general who properly administer divine affairs, how much the more is obedience due to the bishop of that See which the Most High ordained to be above all others, and which is consequently dutifully honored by the devotion of the whole Church.
Also explained or at least tried to. But maybe words of greater mind will be better. So here have the Commentator, Cornelius a Lapide:
Ver. 52. Then Jesus saith to him, Put up again thy sword into his place. Christ here reproves Peters rashness in drawing his sword against His wish. Peters sin, then, was twofold: first in striking against Christs wish, and next, because this was an act not so much of defence as of revenge, which did not help to deliver Christ from the soldiers, but rather excited them the more against Him. But Peter, says S. Chrysostom, was hurried on by his eagerness to protect Christ, and did not think of this, but remembered rather His words, that Christ had ordered them to take two swords, inferring that it was for His defence. And accordingly he thought that in striking the servant he was acting according to the mind of Christ, “Let revenge cease, let patience be exhibited,” says the Interlinear Gloss.
Rest to read here, I recomend it: catholicapologetics.info/scripture/newtestament/26matth.htm
Material sword is given to Emperor. And to all lawful kings, senators, presidents - all lawful authority. But this sword is to be beared for the Church.