What is antinomianism? Antinomianism is not as easy to define as it sounds; it is even more difficult to recognize. The word itself means to be against (anti) law (nomos = law), and so the most basic definition is that an antinomian is one who is against the law of God in some way.
But as Mark Jones has so ably points out in his book on this very subject (Antinomianism: Reformed Theology’s Unwelcome Guest), antinomianism cannot be rightly understood merely in terms of its etymology. In fact, there are many different forms of antinomianism, which makes it even more difficult to define or diagnose.
Perhaps the most common form of antinomianism might be referred to simply as practical antinomianism. 1 John 3:4 speaks of this kind when it says,
“Everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness.” (ESV)
The person who “makes a practice of sinning” lives in such a way as to be without law or anti-law. Licentiousness, then, is a common form of antinomianism, and is probably the form that most readily comes to mind when one thinks of antinomianism in the first place.
But what if I told you that legalism is often just as antinomian at heart as licentiousness? Legalism (ironically enough), when all is said and done, really just devolves into another form of antinomianism. One need look no further than the Pharisees to prove this point. Were the Pharisees anti-law? Did they not teach God’s law? Were they not experts in God’s law? Certainly. But the effect of their teaching was such that it actually led people away from obeying God’s commandments.
In Mark chapter 7 Jesus essentially rebukes them for a form of antinomianism. Of course, He doesn’t use the word itself, but just look at what He says to them in v.6-9:
“And he said to them, “Well did Isaiah prophesy of you hypocrites, as it is written, “‘This people honors me with their lips, but their heart is far from me; in vain do they worship me, teaching as doctrines the commandments of men.’ You leave the commandment of God and hold to the tradition of men.” And he said to them, “You have a fine way of rejecting the commandment of God in order to establish your tradition!” (ESV)
They left and rejected “the commandment of God” (v.8, 9) in order to establish and uphold their own tradition. A legalist may be all about rules, but it is often the case that it is not really God’s rules or commandments that he or she is most concerned about keeping, but rather their own!
In case anyone thought that Jesus was exaggerating, He even gives an example. He mentions their traditional practice of “Corban” (v.11). Notice how Jesus shows us that this was in direct contradiction to the law of Moses. In v.10-11 He tells them,
“Moses said, ‘Honor your father and your mother’; and, ‘Whoever reviles father or mother must surely die.’ But you say, ‘If a man tells his father or his mother, “Whatever you would have gained from me is Corban”’ (that is, given to God)—”
To declare your property as “corban” was to declare it as dedicated or reserved for God. Think of it as leaving property to the church in your will. Once it was declared as “corban,” it could not be sold to be used for other things, even for helping one’s elderly parents who are in need! And what was the result? They, in effect, ‘no longer permitted’ a person to do anything for father or mother! They essentially prevented people from obeying God by their own tradition! And this was not an isolated instance! Jesus adds in v.13, “And many such things you do.”
Think about that for a moment – it is possible to actually teach God’s law, and yet do so in a way that is essentially antinomian at-heart! (See why it can be so difficult to define?) It is not without reason that Jeremiah 17:9 says,
“The heart is deceitful above all things, and desperately sick; who can understand it?”
Here we see that antinomianism & legalism are often really just two sides of the very same coin – they really aren’t that different after all! Were the Pharisees legalists? Certainly. But even so, they were just as antinomian as any licentious person, for they rejected the commandment of God in order to establish their tradition in its place.
Schreiberspace 
This is not antinomianism
It is most certainly a form of practical antinomianism, even if it doesn’t fit neatly with the usual definitions of it.
In both their actual teaching as well as in their practice, the Pharisees were anti-law, even if they thought themselves to be just the opposite. The heart is (as Jeremiah says) deceitful above all things and desperately wicked. Who can know it? They were blind to the true condition of their hearts.
they were called flesh flies by true antinomians