The disciples said, “See, Lord, here are two swords.” “That’s enough!” he replied.
—Gospel of Luke 22:36-38, NIV
Ellul, Yoder and Archie Penner claim that two swords could not possibly have been "enough" to defend Jesus from his pending arrest, trial and execution, so their sole purpose must have been Jesus' wish to fulfill a prophecy (Isaiah 53:9-12).[4] As Ellul explains:
The further comment of Jesus explains in part the surprising statement, for he says: "It is necessary that the prophecy be fulfilled according to which I would be put in the ranks of criminals" (Luke 22:36-37). The idea of fighting with just two swords is ridiculous. The swords are enough, however, to justify the accusation that Jesus is the head of a band of brigands. We have to note here that Jesus is consciously fulfilling prophecy. If he were not the saying would make no sense
Well known theologian John Gill said in his Exposition of the Entire Bible:
These words of Christ are not to be understood literally, that he would have his disciples furnish themselves with swords at any rate, since he would never have said, as he afterwards does, that two were sufficient; which could not be enough for eleven men; or have forbid Peter the use of one, as he did in a very little time after this: but his meaning is, that wherever they came, and a door was opened for the preaching of the Gospel, they would have many adversaries, and these powerful, and would be used with great violence, and be followed with rage and persecution; so that they might seem to stand in need of swords to defend them: the phrase is expressive of the danger they would be exposed to, and of their need of protection; and therefore it was wrong in them to be disputing and quarrelling about superiority, or looking out for, and expecting temporal pomp and grandeur, when this would be their forlorn, destitute, and afflicted condition; and they would quickly see the affliction and distress begin in himself. In "seven" ancient copies of Beza's, it is read in the future tense, "he shall take, he shall sell, he shall buy".
http://en.wikipedia.org/wiki/Sell_your_cloak_and_buy_a_sword