"Traditional proof-texting debate for and against pacifism has always made much of the 'two swords' passage. If Jesus had meant his disciples never to kill why would he now have told them to arm? Is he not preparing them for legitimate defense while on their post-Pentecost missionary travels? But Jesus says he is preparing them for his capture, for the fulfillment of the prediction that he would be found among compromising company. When they respond, 'We have two swords,' his response, 'Enough,' cannot mean that two swords would be enough for the legitimate self-defense against bandits of twelve missionaries traveling two by two. He is (in direct parallel to Deut. 3:26, where YHWH tells Moses to change the subject, LXX hikanon estin) breaking off the conversation because they don't understand anyway.
"According to Hans Werner Bartsch...the reference to Isa. 53:12 cannot be Luke's insertion, for it is not according to the Septuagint. Luke in any case does not give to the fulfillment of prophecy the recurrent function it has for Matthew. This makes it all the more striking that just here, as in Luke 24:26 (dealing also with the suffering of the Messiah), the theme of fulfillment should be thus accented. In the Matthew account of the sword in the garden (26:54) the reference to fulfillment is in Jesus' own words (rather than, as usual in Matthew, the Evangelist's) and likewise centers upon the sword. Thus the 'fulfillment of prophecy' theme has a special link to the garden capture in both Gospels."
--John Howard Yoder, The Politics of Jesus (2nd ed.; Grand Rapids: Eerdmans, 1972, 1994), 45n.44