Mat 26:55 Have you come out as against a thief with swords and staves to take me? I sat daily with you teaching in the temple, and you laid no hold on me.
Mat 26:56 But all this was done, that the scriptures of the prophets might be fulfilled.
Alternative: Have you come upon a robber with swords and clubs to arrest me? Throughout the day, I sat near you teaching and you did not seize me. But this whole thing came into being in order to complete the prophet's picture.
In the NIV study Bible, they translated "thief" as "rebel," adding a bit of historical politics into the text where it cannot be found in the original. While NIV is useful, the idea of translating Christ's words to add meaning that isn't in the original text is wrong-headed.
In the previous two verses, Christ makes it clear that he could avoid his fate but that he desired to personally complete an historical mission, one foreseen by the prophets.
Here, he points out that those who are taking him are playing their part in that historical mission as well. Why did their attitude toward him suddenly change? There was no proximate cause for them to bring arms against him. Instead, there was an underlying history. Part of that history, Christ has already talked about: the history of killing prophets. The other part of that history, that is, completing the prophecies of the Old Testament is yet to come.
Do the people involved have a choice in this matter? Christ has already said that he had a choice so we much assume that they do as well. In one sense, their reactions are predictable. People always turn on those who point the error of their ways. This isn't a Jewish trait. It is a human trait. The Greeks killed Socrates for the same type of crimes against humanity.
However, Christ's death was different. It was prophesied as something that had to happen in a certain way because, from the perspective of a timeless God, it is happening in that way. People have choices, but a mind that transcends time knows what those choices are. From the divine perspective, these acts were not at one time yet to happen, nor have they happened in the past. From the divine perspective, all of history is happening now. Everyone's choices are being made now.
In his connection with the divine, Christ often deals with time in ways that are difficult for us to understand. This analysis is based upon that fact: the idea that he knew how his words would be recorded and phrased every word so that they would have meaning for us today as they had an immediate meaning for those around him.
At every point in time, people are taking arms against God's will in one way or another
"Thieves" is from lêistês (lestes), which means "robber" or "pirate."
"To take" is from sullambanô (sullambano), which means "to collect," "to gather together," "to carry off," "to put together," "to sieze," "to apprehend," "to arrest," "to enjoy together," "to take with," and "to take part in."
"Sat" is from kathezomai (kathezomai), which means "to sit down," "to take one's seat," "to occupy," "to remain seated," and "to preside."
"Teaching" is from didaskô (didasko), which means "to teach," "to instruct," "to indicate," "to explain," and "to give sign of."
"Temple" is from hieros (hieron) which means "filled with or manifesting divine power," "holy," "consecrated," "under divine protection," "holy place," "sacred principle," and "supernatural."
"Laid hold" is from krateô (krateo), which means "to rule," "to hold sway," "to be the lord and master," "to conquer," "to prevail over," "to get the upper hand," "to seize," "to control," and "to command."
"Was done" is from gignomai (ginomai), which means "to become," "to come into being," "to be produced," and "to be."
"Scriptures" is from graphê (graphe), which means "representing by means of lines," "a drawing," "writing," "the art of writing," and "that which is written." It came to mean "scripture" from its use in the Gospels.
"Fulfilled" is plêroô (pleroo), which mean "to fill," "to fulfill," "to make complete," "to pay in full," "to make pregnant," and "to fill full."