I love seeing that passage from Luke quoted out of context - it would have taken reading just a couple more lines to see what it was about:
From Luke 22
34 He said, "I tell you, Peter, the cock will not crow this day, until you three times deny that you know me." 35 And he said to them, "When I sent you out with no purse or bag or sandals, did you lack anything?" They said, "Nothing." 36 He said to them, "But now, let him who has a purse take it, and likewise a bag. And let him who has no sword sell his mantle and buy one. 37 For I tell you that this scripture must be fulfilled in me, 'And he was reckoned with transgressors'; for what is written about me has its fulfilment." 38 And they said, "Look, Lord, here are two swords." And he said to them, "It is enough." 39 And he came out, and went, as was his custom, to the Mount of Olives; and the disciples followed him. 40 And when he came to the place he said to them, "Pray that you may not enter into temptation." 41 And he withdrew from them about a stone's throw, and knelt down and prayed, 42 "Father, if thou art willing, remove this cup from me; nevertheless not my will, but thine, be done." 43 * [No text] 44 * [No text] 45 And when he rose from prayer, he came to the disciples and found them sleeping for sorrow, 46 and he said to them, "Why do you sleep? Rise and pray that you may not enter into temptation." 47 While he was still speaking, there came a crowd, and the man called Judas, one of the twelve, was leading them. He drew near to Jesus to kiss him; 48 but Jesus said to him, "Judas, would you betray the Son of man with a kiss?" 49 And when those who were about him saw what would follow, they said, "Lord, shall we strike with the sword?" 50 And one of them struck the slave of the high priest and cut off his right ear. 51 But Jesus said, "No more of this!" And he touched his ear and healed him.
Jesus never advocated the taking up of swords, except for a brief time, in order to fulfill prophecy. His instruction that they take up swords is the same as his warning to Peter: his disciples were to abandon him and the ways he taught them out of fear (Peter denied because of fear; Judas wanted a purse full of silver out of fear; and his other disciples wanted arms out of fear. Jesus allowed, albeit with some clear sarcasm, his disciples to betray him and his ways, but this was so that seeing their own weakness, they could turn to him later and be strengthened by his forgiveness. Only Judas did not repent - probably because without faith that Jesus was in charge of what was happening to him, he despaired for Jesus and commited suicide, instead of trusting and turning back to him.
Jesus tolerated the disciples to take up swords for a brief three hours, but as soon as they had drawn them, he permanently forbade them. And then having compassion, he immediately healed the soldier, whose ear was struck off.