Actually, the passage structure and Greek structure tells a different story.
Christ is contrasting what will come from what existed before.
(Specifically, it is a “counter-point/point” structural marker. Verse 35 “when I sent you out you didn’t lack *anything*../..” verse 36 “but now”)
How will it differ?
First, Christ answers Peter’s boast by showing the intensity of the persecution to come, “Jesus answered, “I tell you, Peter, before the rooster crows today, you will deny three times that you know me.” It will be that bad.
Then, Christ names the items, including the sword, As necessary now, in contrast to the situation that existed when the disciples had been sent out before.
“Then Jesus asked them, “When I sent you without purse, bag or sandals, did you lack anything?”
“Nothing,” they answered.”
The Greek structural focus of the supporting marker in sentence, is that Christ will be numbered with transgressors and this fulfillment of prophecy must happen and would change everything.
That change is positioned in Greek sentence structure as the supporting justification as to why the disciples needed these items including a sword.
This situation is a 180 degree turn from before, when He was welcomed and his disciples commanded respect.
(I mentioned earlier that it was not the presence of swords that Christ was charged with, but opposing Ceasar. )
Best
Nevertheless, Jesus demonstrates that he did not need guys with swords to keep the soldiers at bay: He could do it with a word. (John 18:6)
Second, He actually says the purpose of the swords is to fulfill prophecy (Luke 22:36):
"... if you don’t have a sword, sell your cloak and buy one. For it is written: ‘he was numbered with the transgressors’; and I tell you that this must be fulfilled in me. Yes, what is written about me is reaching its fulfillment."