Not to add any fuel to bro Willi's insanity, but the reason Jesus told them to go and buy a sword was so that the scripture could be fulfilled that He was numbered among transgressors...
"And He said to them, "When I sent you out without purse and bag and sandals, you did not lack anything, did you?" And they said, "No, nothing." And He said to them, "But now, let him who has a purse take it along, likewise also a bag, and let him who has no sword sell his robe and buy one. "For I tell you, that this which is written must be fulfilled in Me, 'And He was numbered with transgressors'; for that which refers to Me has its fulfillment." And they said, "Lord, look, here are two swords." And He said to them, "It is enough....
... And when those who were around Him saw what was going to happen, they said, "Lord, shall we strike with the sword?" And a certain one of them struck the slave of the high priest and cut off his right ear. But Jesus answered and said, "Stop! No more of this." And He touched his ear and healed him"
