Don't think I've come to release people from the Torah or the prophets. I haven't come to loosen them but to fulfill them.
Indeed, until Heaven and Earth pass away, not one dot will be taken from the law until its purpose is completed. So whoever releases one of the least of these commandments, and teaches men so, shall be called least under God's reign; but anyone who does them and teaches them will be considered great.
Until your righteousness transcends that of the scribes and Pharisees, you will not be living under God's rule.
This is problematic for a number of reasons.
The Torah as known to most of Jesus' hearers was not a manuscript they could read but a shared oral tradition. [Richard Horsley is very good on this point, but online I'm finding only ads for his books, and a review that summarizes his conclusions: http://www.thetwocities.com/book-reviews/review-of-text-and-tradition-in-performance-and-writing-by-richard-horsley/ ]
It was not a scroll on the shelves in the Temple in Jerusalem (although this is the kind of source in which modern people encounter it) but a body of common knowledge that people knew and discussed fairly often -- but which wasn't entirely uniform between Judea, Samaria and Galilee (an area which had had 'the laws of the Judeans' forcibly imposed on it around 100 years previously, and probably still followed local Isrealite custom to a great degree.) The Pharisees, of course, were agreed on the version of Judea, which probably put more stress on centralized worship in the Temple, less on customs that kept peasant families intact & in secure possession of their ancestral land.
The Pharisees of Jesus' time were dominated by the rigid and ethnocentric interpretations of Shammai ( http://en.wikipedia.org/wiki/Hillel_and_Shammai ), and from that standpoint would certainly have accused Jesus of relaxing the law. Jesus' interpretations are usually close to those of Shammai's rival Hillel, whose rulings had fallen out of acceptance -- except in one practice highly significant to Jesus' audience: the Proszul. (http://en.wikipedia.org/wiki/Prozbul)
This innovation, although well intended (to make loans available for subsistence farmers) had eventually led to a plague of foreclosures, resulting in widespread destitution, malnuitrition, the sheer multitude of diseases & unhealed injuries Jesus is called to address. This would certainly be an example of 'releasing one of God's commandments, and teaching men so', in that Hillel had been one of the Pharisees' two most prominent teachers.
In Luke, the closest thing to this passage is probably Luke 16:17, "It is easier for Heaven and Earth to pass away than for one dot of the law to become void." There, however, it immediately follows Luke 16:16, "The Law and the prophets were until John; since then the good news of God's reign is preached; and everyone is pushing to get there." That implies a considerably different view of when and how the Torah applies to people.
One reading of the Bible overall is that God produced and 'chose' the people called 'Israel' to help overcome the state of divine/human estrangement produced by 'The Knowledge of Good and Evil.' If that was the function of this people, it suggests that this is the purpose their laws were intended to serve.
Jesus' practice seems to treat these laws as guidelines. That is, one would not want to ignore a generally helpful set of guidelines, but it wouldn't be a crime to make occasional exceptions for good reason. [The rabbis who wrote the Talmud spent considerable effort arguing about one law, that which demanded that an incorrigibly insubordinate son should be taken out & stoned -- a law which they eventually concluded had no possible application and no reason to exist except "so we could have this argument."